Amantadine compositions and methods of use

ABSTRACT

Methods of nighttime administration of amantadine to reduce sleep disturbances in patient undergoing treatment with amantadine are described, as well as compositions of extended release amantadine that are suitable for nighttime administration.

CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No. 14/267,597, filed May 1, 2014, which is a continuation of U.S. patent application Ser. No. 12/959,321, filed Dec. 2, 2010, now U.S. Pat. No. 8,741,343, which claims benefit of U.S. Provisional Application No. 61/266,053, filed Dec. 2, 2009, all of which applications are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The field of the invention is extended release compositions of amantadine and uses thereof.

Amantadine is indicated for various conditions that can be treated by NMDA receptor antagonists including the treatment of idiopathic Parkinson's disease (Parlysis Agitans), postencephalitic Parkinsonism, and symptomatic Parkinsonism which may follow injury to the nervous system by carbon monoxide intoxication. Amantadine also has activity as a viral M2 channel inhibitor and is used for the prophylaxis and treatment of infection of viral diseases, especially influenza A virus.

Currently marketed forms of amantadine are immediate release formulations that are typically administered two or more times a day. Amantadine's use is limited by dose related CNS side effects including dizziness, confusion, hallucinations, insomnia and nightmares (Gracies J M, Olanow C W; Current and Experimental Therapeutics of Parkinson's Disease; Neuropsychopharmacology: the Fifth Generation of Progress, p. 1802; American College of Neuropsychopharmacology 2002), which can be particularly exacerbated when amantadine is administered at night.

It is known that immediate release amantadine can act as a stimulant, causing insomnia and sleep disturbance. Therefore, the last dose is typically administered no later than 4 pm in order to minimize these side effects. Such dosing of amantadine results in peak plasma amantadine concentrations occurring in the evening or night, and very low plasma concentrations in the morning.

Extended release forms of amantadine have been described in the art. U.S. Pat. No. 5,358,721, to Guittard et al., and U.S. Pat. No. 6,217,905, to Edgren et al., each disclose an oral osmotic dosage form comprising an antiviral or anti-Parkinson's drug, respectively, where in each case amantadine is listed as a possible drug to be utilized in the dosage form. U.S. Pat. No. 6,194,000, to Smith et al., discloses analgesic immediate and controlled release pharmaceutical compositions utilizing NMDA receptor antagonists, such as amantadine, as the active agent. U.S. Patent Appl. Publication Nos. US 2006/0252788, US 2006/0189694, US 2006/0142398, and US 2008/0227743, all to Went et al., each disclose the administration of an NMDA receptor antagonist, such as amantadine, optionally in controlled release form.

SUMMARY OF THE INVENTION

The inventors have identified a need in the art for improved formulations of amantadine that result in a patient having higher plasma concentrations of amantadine upon waking in the morning without adversely affecting sleep. Further, the inventors have identified a need in the art for a method of administering amantadine in the late afternoon or evening, e.g. after 4 pm, which reduces side effects of insomnia and sleep disturbance and provides effective plasma concentrations of amantadine upon waking.

Therefore, there exists a need in the art for improved methods of amantadine therapy which can be administered to a patient shortly before they wish to sleep (e.g., at bedtime) without causing insomnia or sleep disturbance. In addition, there is a need for an amantadine therapy which can be taken by the patient before they go to sleep and then provides a suitable plasma concentration of amantadine when they wake up, e.g. in the morning, after a full night's sleep.

In addition, many Parkinson's disease patients have difficulty swallowing and are on multiple medications. Hence there is a need for amantadine therapy that delivers a therapeutically effective dose of the drug, can be administered once daily and is in an oral dosage form that is small in size and does not unduly increase the pill burden.

One aspect of the invention is a method of administering amantadine to a patient in need thereof, said method comprising orally administering an extended release (ER) composition comprising amantadine, or a pharmaceutically acceptable salt thereof, less than three hours before bedtime (i.e. the time at which the subject wishes to go to sleep for the night). This aspect also includes the use of such compositions and the use of amantadine for the manufacture of a medicament as described below. Alternatively, the composition is administered less than about 4 hours before bedtime.

In a second aspect, the invention provides a method of reducing sleep disturbance in a human subject undergoing treatment with amantadine, said method comprising administering an extended release (ER) composition comprising amantadine, or a pharmaceutically acceptable salt thereof, less than about three hours before bedtime (i.e. the time at which the subject wishes to go to sleep for the night). This aspect also includes the use of such compositions and the use of amantadine for the manufacture of a medicament as described below. Alternatively, the composition is administered less than about 4 hours before bedtime.

In a third aspect, the invention provides a method of treating levodopa induced dyskinesia, or fatigue, or dementia, or any other symptom of Parkinson's disease, said method comprising administering an extended release (ER) composition comprising amantadine, or a pharmaceutically acceptable salt thereof, less than about three hours before bedtime (i.e. the time at which the subject wishes to go to sleep for the night). This aspect also includes the use of such compositions and the use of amantadine for the manufacture of a medicament as described below.

In a fourth aspect, the invention provides a method of treating brain injury, brain trauma, dementia, Alzheimer's disease, stroke, Huntington's disease, ALS, Multiple Sclerosis, neurodegenerative diseases, dementias, cerebrovascular conditions, movement disorders, cranial nerve disorders, neuropsychiatric disorders, said method comprising administering an extended release (ER) composition comprising amantadine, or a pharmaceutically acceptable salt thereof, less than about three hours before bedtime (i.e. the time at which the subject wishes to go to sleep for the night). This aspect also includes the use of such compositions and the use of amantadine for the manufacture of a medicament as described below.

In one embodiment of any of the above aspects, administration occurs less than two and a half, less than two, less than one and a half, less than one or less than half hour before bedtime (i.e. the time at which the subject wishes to go to sleep for the night).

In one embodiment of any of the above aspects the patient has been diagnosed with Parkinson's disease.

In one embodiment of any of the above aspects, the composition is administered once daily. In another aspect, the daily dose exceeds 200 mg, and is given in 1, 2 or 3 capsules of size 0, 1 or 2.

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in levodopa induced dyskinesia (LID). In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80% reduction in levodopa induced dyskinesia. In further embodiments, the reduction in levodopa induced dyskinesia is measured on a numeric scale that is used by the FDA to evaluate effectiveness of drugs indicated to reduce LID. In further specific embodiments, the scale used in measuring the reduction in LID could be UDysRS, UPDRS Part IV (subscores 32, 33), Dyskinesia Rating Scale (DRS), Abnormal Involuntary Movement Scale (AIMS), or other scales developed for this purpose.

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in Parkinson's disease fatigue. In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60% reduction in Parkinson's disease fatigue. In further specific embodiments, the reduction in fatigue is measured on a numeric scale that is used by the FDA to evaluate effectiveness of drugs indicated to reduce fatigue. In further specific embodiments, the scale used in measuring the reduction in fatigue could be the Fatigue Severity Scale (FSS).

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in Parkinson's disease symptoms. In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40% reduction in Parkinson's symptoms. In further specific embodiments, the reduction in Parkinson's symptoms is measured on a numeric scale that is used by the FDA to evaluate effectiveness of drugs indicated to reduce Parkinson's symptoms. In further specific embodiments, the scale used in measuring the reduction in Parkinson's symptoms could be the Unified Parkinson's Disease Rating Scale (UPDRS).

In one embodiment of any of the above aspects, the composition is added to food, and in a more specific embodiment to a small amount of soft food (e.g. applesauce or chocolate pudding), prior to administration. Addition to food may involve a capsule being opened and the contents sprinkled over the patient's food. This is advantageous if the patient is unable or unwilling to swallow the composition.

In one embodiment of any of the above aspects, there is no increase in plasma concentration of amantadine for at least one hour after the administration at steady state plasma concentrations.

In one embodiment of any of the above aspects, there is no increase in the plasma concentration of amantadine for at least two hours after the administration at steady state plasma concentrations.

In one embodiment of any of the above aspects, the administration of the composition to a human subject at steady state amantadine plasma concentrations increases the amantadine plasma concentration by less than 5%, 10%, 15%, 20% or 25% at 1, 2, 2.5 or 3 hours following such administration. For example, administration of the composition to a human subject at steady state amantadine plasma concentrations increases the amantadine plasma concentration by less than 5% at 1, 2, 2.5 or 3 hours following such administration; or by less than 10% at 1, 2, 2.5 or 3 hours following such administration; or by less than 15% at 1, 2, 2.5 or 3 hours following such administration; or by less than 20% at 1, 2, 2.5 or 3 hours following such administration; or by less than 25% at 1, 2, 2.5 or 3 hours following such administration.

In one embodiment of any of the above aspects the amantadine has a single dose Tmax of 9 to 15 hours. In a more specific embodiment, the amantadine has a single dose Tmax of 10 to 14 hours after administration. In another more specific embodiment, the amantadine has a single dose Tmax of 11 to 13 hours after administration.

In one embodiment of any of the above aspects the amantadine has a steady state Tmax of 7 to 13 hours. In a more specific embodiment, the amantadine has a steady state Tmax of 8 to 12 hours after administration. In another more specific embodiment, the amantadine has a steady state Tmax of 9 to 11 hours after administration.

In one embodiment of any of the above aspects peak plasma concentration of amantadine is achieved between 6 and 16 hours after administration of a single dose of the composition. In a more specific embodiment, peak amantadine plasma concentration is achieved 8 to 14 hours after administration of a single dose of the composition. In another more specific embodiment, peak amantadine plasma concentration is achieved 10 to 12 hours after administration of a single dose of the composition. In additional specific embodiments, peak amantadine plasma concentration is achieved between 6, 7, 8, 9, 10, 11 or 12 hours to about 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours after administration of a single dose of the composition.

In one embodiment of any of the above aspects, a once daily oral administration of the composition to a human subject provides a steady state plasma concentration profile characterized by a concentration increase of amantadine of less than 25% at three hours after the administration. In a more specific embodiment, the steady state plasma concentration profile is characterized by a concentration increase of amantadine of less than 25% at four hours after the administration.

In one embodiment of any of the above aspects, the composition is administered once a day and the ratio of Cmax to Cmin at steady state is 1.5 to 2.0, or, more specifically, 1.7 to 1.9, or, more specifically, about 1.8.

In one embodiment of any of the above aspects, the steady state plasma concentration profile following multiple administrations to a human subject of the composition at bedtime is characterized by an average plasma concentration during the day (“C-ave-day”, defined as the average day time amantadine plasma concentration as measured in a human PK study) that is 1.1 to 2.0 times the average plasma concentration during the night (“C-ave-night”, defined as the average night time amantadine plasma concentration as measured in a human PK study). In more specific embodiments the C-ave-day is the average amantadine plasma concentration as measured between the hours of 5 am, 6 am, 7 am, 8 am or 9 am to the hours of 4 pm, 5 pm, 6 pm, 7 pm or 8 pm; for example, between the hours of 6 am and 4 pm, between the hours of 7 am and 6 pm, or between the hours of 7 am and 5 pm. The C-ave-night is the average amantadine plasma concentration as measured between the hours of 4 pm, 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm or 11 pm to the hours of 5 am, 6 am, 7 am, 8 am or 9 am; for example, between the hours of 10 pm and 6 am, between the hours of 7 pm and 6 am, or between the hours of 8 pm and 6 am.

In one embodiment of any of the above aspects, the steady state plasma concentration profile following multiple administrations to a human subject of the composition at bedtime is characterized by an average plasma concentration during the morning (“C-ave-morning”, defined as the average amantadine plasma concentration as measured in a human PK study during the morning hours) that is 1.1 to 2.0 times the average plasma concentration during the night. In one embodiment the C-ave-morning is the average amantadine plasma concentration as measured between the hours of 5 am, 6 am, 7 am, 8 am or 9 am to the hours of 11 am, 11:30 am, 12 pm, 12:30 pm or 1:00 pm; for example, between the hours of 5 am and 11 am, or between the hours of 7 am and 12 pm. More preferably, the ratio of C-ave-morning/C-ave-night at steady state is 1.2 to 1.6.

In one embodiment of any of the above aspects, the steady state plasma concentration profile following daily administration of the composition is characterized by an average plasma concentration during the period 8 hours to 12 hours after administration (“C-ave-8-12 hrs”) that is 1.1 to 2.0 times the average plasma concentration during the first 8 hours after administration (“C-ave-0-8 hrs”). More preferably, the ratio of C-ave-8-12 hrs/C-ave-0-8 hrs at steady state is 1.2 to 1.6.

In one embodiment of any of the above aspects, administration of a single dose of the composition to a human subject provides a plasma concentration profile characterized by: a fractional AUC from 0 to 4 hours that is less than 5%, and preferably less than 3% of AUC_(0-inf); a fractional AUC from 0 to 8 hours that is about 5 to 15%, and preferably about 8 to 12% of AUC_(0-inf); a fractional AUC from 0 to 12 hours that is about 10 to 40%, and preferably about 15 to 30% of AUC_(0-inf); a fractional AUC from 0 to 18 hours that is about 25 to 60%, and preferably about 30 to 50% of AUC_(0-inf); and a fractional AUC from 0 to 24 hours that is about 40 to 75%, and preferably about 50 to 70% of AUC_(0-inf).

In one embodiment of any of the above aspects, a once daily oral administration of the composition to a human subject provides a steady state plasma concentration profile characterized by: a fractional AUC from 0 to 4 hours that is about 2 to 25%, and preferably about 5 to 20% of AUC₂₄; a fractional AUC from 0 to 8 hours that is about 15 to 50%, and preferably about 20 to 40% of AUC₂₄; a fractional AUC from 0 to 12 hours that is about 30 to 70%, and preferably about 40 to 60% of AUC₂₄: and a fractional AUC from 0 to 18 hours that is about 60 to 95%, and preferably about 75 to 90% of AUC₂₄.

In one embodiment of any of the above aspects, a once daily oral administration of the composition to a human subject provides a steady state plasma concentration profile characterized by: a fractional AUC from 0 to 8 hours that is about 15 to 40%, and preferably about 20 to 32% of AUC₂₄; a fractional AUC from 8 to 16 hours that is about 30 to 50%, and preferably about 35 to 45% of AUC₂₄; and a fractional AUC from 16 to 24 hours that is about 20 to 35%, and preferably about 25 to 33% of AUC₂₄.

In one embodiment of any of the above aspects the amantadine is administered as a pharmaceutically acceptable salt. In a more specific embodiment, the amantadine is administered as hydrochloride or amantadine sulfate.

In one embodiment of any of the above aspects, a total daily dose of 50 mg to 600 mg of amantadine, or a pharmaceutically acceptable salt thereof is administered to a patient. More specifically the daily dose of amantadine or pharmaceutically acceptable salt thereof administered may be in the range of 100 to 440 mg. In another specific embodiment, the daily dose of amantadine or pharmaceutically acceptable salt thereof maybe in the range of 260 to 420 mg. In another embodiment, the daily dose of amantadine or pharmaceutically acceptable salt thereof administered exceeds 300 mg per day. In various specific embodiments, the daily dose of amantadine or pharmaceutically acceptable salt thereof may be 50 to 75 mg, 70 to 95 mg, 90 to 115 mg, 110 to 135 mg, 130 to 155 mg, 150 to 175 mg, 170 to 195 mg, 190 to 215 mg, 210 to 235 mg, 230 to 255 mg, 250 to 275 mg, 270 to 295 mg, 290 to 305 mg, 300 to 315 mg, 310 to 325 mg, 320 to 335 mg, 330 to 345 mg, 340 to 355 mg, 350 to 365 mg, 360 to 375 mg, 370 to 385 mg, 380 to 395 mg, 390 to 405 mg, 400 to 415 mg, 410 to 425 mg, 420 to 435 mg, 430 to 445 mg or 440 to 455 mg.

In one embodiment of any of the above aspects, the composition comprises 50 mg to 600 mg of amantadine, or a pharmaceutically acceptable salt thereof. More specifically, the composition may comprise 100 mg to 450 mg of amantadine, or a pharmaceutically acceptable salt thereof. Still more specifically, the composition may comprise 130-210 mg of amantadine, or a pharmaceutically acceptable salt thereof. In various specific embodiments, a dosage form containing the composition comprises 50 to 75 mg, 70 to 95 mg, 90 to 115 mg, 110 to 135 mg, 130 to 155 mg, 150 to 175 mg, 170 to 195 mg, 190 to 215 mg, 210 to 235 mg, 230 to 255 mg, 250 to 275 mg, 270 to 295 mg, 290 to 305 mg, 300 to 315 mg, 310 to 325 mg, 320 to 335 mg, 330 to 345 mg, 340 to 355 mg, 350 to 365 mg, 360 to 375 mg, 370 to 385 mg, 380 to 395 mg, 390 to 405 mg, 400 to 415 mg, 410 to 425 mg, 420 to 435 mg, 430 to 445 mg or 440 to 455 mg of amantadine, or a pharmaceutically acceptable salt thereof. In a more specific embodiment, the composition comprises about 110, 120, 130, 140, 150, 160 170, 180, 190, 210, or 220 mg amantadine, or a pharmaceutically acceptable salt thereof. In another more specific embodiment, the composition comprises 110 mg amantadine hydrochloride. In another more specific embodiment, the composition comprises 130 mg amantadine hydrochloride. In another more specific embodiment, the composition comprises 170 mg amantadine hydrochloride. In another more specific embodiment, the composition comprises 210 mg amantadine hydrochloride.

In one embodiment of any of the above aspects, the composition is administered as one, two, three or four unit dosage forms each comprising 100 to 175 mg amantadine, or a pharmaceutically acceptable salt thereof. In a more specific embodiment, the composition is administered as two unit dosage forms each comprising 100 to 175 mg amantadine, or a pharmaceutically acceptable salt thereof.

In one embodiment of any of the above aspects, the composition is administered as one, two, or three unit dosage forms each comprising 50 to 250 mg amantadine, or a pharmaceutically acceptable salt thereof. In a more specific embodiment, the composition is administered as one or two unit dosage forms each comprising 65 to 220 mg amantadine, or a pharmaceutically acceptable salt thereof.

In one embodiment of any of the above aspects, oral administration of a single dose of the composition to a human subject in a fasted state provides a maximum plasma concentration (Cmax) of 1.0 to 2.8 ng/ml per mg of amantadine. In a more specific embodiment, oral administration of a single dose of the composition to a human subject in a fasted state provides a maximum plasma concentration (Cmax) of 1.6 to 2.4 ng/ml per mg of amantadine and an AUC_(0-inf) (Area under the concentration-curve curve from t=0 to t=infinity) of 40 to 75 ng*h/mL per mg of amantadine.

In one embodiment of any of the above aspects, the daily oral administration of a dose of the composition to a human subject provides a steady state plasma concentration profile characterized by at least one of: (i) a Cmax of 2.4 to 4.2 ng/ml per mg of amantadine, (ii) a Cmin of 1.1 to 2.6 ng/ml per mg of amantadine, and (iii) an AUC₀₋₂₄ of 44 to 83 ng*h/mL per mg of amantadine. In a more specific example, all three criteria of (i), (ii) and (iii) are met.

In a more specific embodiment, the steady state plasma concentration profile is further characterized by: (iv) no increase in concentration of amantadine for at least one hour after the administration; and (v) Cmax/Cmin ratio of 1.5 to 2.0. In a more specific embodiment, both criteria of (iv) and (v) are met.

In another more specific embodiment, the steady state plasma concentration profile is further characterized by at least one of: (iv) no increase in plasma concentration of amantadine for at least two hours after the administration; and (v) a Cmax/Cmin ratio of 1.7 to 1.9. In a more specific embodiment, both criteria of (iv) and (v) are met.

In one embodiment of any of the above aspects the composition has an in vitro dissolution profile of amantadine which shows at least one of (i) not more than 25% dissolution at 2 hours, (ii) not more 55-85% dissolution at 6 hours, and (iii) at least 80% dissolution at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In a more specific embodiment two of criteria (i), (ii) and (iii) are met. In a more specific embodiment, all three of criteria (i), (ii) and (iii) are met.

In one embodiment of any of the above aspects the composition has an in vitro dissolution profile of amantadine which shows at least one of (i) not more than 25% dissolution at 2 hours, (ii) not more than 25-55% dissolution at 6 hours, and (iii) at least 80% dissolution at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In a more specific embodiment two of criteria (i), (ii) and (iii) are met. In a more specific embodiment, all three of criteria (i), (ii) and (iii) are met.

In one embodiment of any of the above aspects the composition has an in vitro dissolution profile of amantadine which shows at least one of (i) not more than 20% dissolution at 1 hour, (ii) about 25-45% dissolution at 2 hours, (iii) not more than 50-80% dissolution at 4 hours, and (iv) at least 80% dissolution at 8 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In a more specific embodiment two of criteria (i), (ii), (iii) and (iv) are met. In a more specific embodiment, all four of criteria (i), (ii), (iii) and (iv) are met.

In one embodiment of any of the above aspects the in vitro dissolution profile of amantadine is further characterized by release of amantadine of: (i) not more than 10% at 1 hour, or (ii) 30-50% at 4 hours, or (iii) at least 90% at 12 hours using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In a more specific embodiment two of criteria (i), (ii) and (iii) are met. In a more specific embodiment, all three criteria of (i), (ii) and (iii) are met.

In another aspect, the present invention provides a pharmaceutical composition comprising or consisting of a pellet-in-capsule, wherein a pellet comprises a core that comprises a core seed with a mixture of amantadine and a binder coated onto the core seed, and an extended release coating surrounding the core comprising ethyl cellulose, a pore forming agent such as hydroxypropyl methyl cellulose or povidone, and a plasticizer.

In another aspect, the present invention provides a pharmaceutical composition for use in the methods of the aspects described above, wherein said composition is for oral administration and comprises a capsule for oral administration, said capsule comprising a plurality of pellets, each pellet comprising: (a) a pellet core comprising amantadine, or a pharmaceutically acceptable salt thereof, and (b) an extended release coating surrounding the pellet core.

In one embodiment, the extended release coating comprises ethyl cellulose and at least one of povidone and hydroxypropyl methyl cellulose, and a plasticizer. In a more specific embodiment, the extended release coating comprises ethyl cellulose, povidone, and a plasticizer.

In one embodiment, the pellet core comprises amantadine and a binder coated onto a core seed. In one embodiment, the core seed is a sugar sphere (nonpareil) or microcrystalline cellulose seed (e.g. Celphere®). In a more specific embodiment, the core seed is a microcrystalline cellulose core. In another specific embodiment, the core seed has a diameter in the range of 100 microns to 1,000 microns. In additional specific embodiments, the core seed has a diameter of 100, 200, 300, 400, 500, 600 or 700 microns. In preferred specific embodiments, the core seed has a diameter of less than 500 microns.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the amantadine, or a pharmaceutically acceptable salt thereof, is present in amounts from 20 to 80 wt %, with a bulk density of 0.3 to 1.2 g/cm³.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the amantadine, or a pharmaceutically acceptable salt thereof, is present in amounts from 40 to 60 wt %, with a bulk density of 0.5 to 1.2 g/cm³.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the amantadine, or a pharmaceutically acceptable salt thereof, is present in amounts from 60 to 80 wt %, with a bulk density of 0.5 to 1.2 g/cm³.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the binder is present in amounts from 8 to 25 wt %.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the core seed is present in amounts from 8 to 25 wt %.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the ethyl cellulose is present in amounts from 10 to 20 wt %.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the povidone is present in amounts from 1 to 4 wt %.

In one embodiment, based on the combined weight of the pellet core and extended release coating, and the plasticizer is present in amounts from 1 to 4 wt %.

In one embodiment, the coated pellet has a diameter in the range of 200 microns to 1700 micros. In additional specific embodiments, the coated pellet has a diameter of 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300 or 1500 microns. In certain specific embodiments, the coated pellet has a diameter of less than 1000 microns, e.g., from 500 to 1000 microns.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the binder is present in amounts from 5 to 25 wt %.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the core seed is present in amounts from 1 to 15 wt %.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the ethyl cellulose is present in amounts from 5 to 20 wt %.

In one embodiment, based on the combined weight of the pellet core and extended release coating, the povidone is present in amounts from 0.25 to 4 wt %.

In one embodiment, based on the combined weight of the pellet core and extended release coating, and the plasticizer is present in amounts from 0.25 to 4 wt %.

In one embodiment, the pellet further comprises a seal coating between the pellet core and the extended release coating. In some embodiments, an inert coating can be applied to the inert core prior to drug coating or on drug-coated pellets or on controlled release coated pellets. In another embodiment, an enteric coating can be applied to the drug coated pellets or controlled release pellets.

In one embodiment, the pellet core comprises a binder, selected from the group consisting of hydroxypropyl methyl cellulose, copovidone, and mixtures thereof.

In one embodiment, the above composition is provided in a size 3, size 2, size 1, size 0 or size 00 capsule.

In one embodiment, the therapeutically effective daily dose of the above composition is administered in no more than two capsules. In another embodiment, the therapeutically effective daily dose of the composition is administered in no more than three size 1 capsules. In another embodiment, the therapeutically effective daily dose of the composition is administered in no more than two size 0 capsules. In a still more preferred embodiment, the therapeutically effective daily dose of the composition is administered in no more than two size 1 capsules. In another embodiment, the therapeutically effective daily dose of the composition is administered in no more than three size 2 capsules.

In a preferred embodiment, the above composition is provided in an amount of 50 to 110 mg of amantadine or a pharmaceutically acceptable salt thereof in a size 2 capsule, and in the amount of 110 mg to 210 mg of amantadine or a pharmaceutically acceptable salt thereof in a size 1 capsule. In additional embodiments, the above composition comprises coated pellets of diameter 300 to 1000 microns, with amantadine or pharmaceutically acceptable salt thereof content of 40-80% wt % and at a bulk density of 0.5-1.2 g/cm³. In a further preferred embodiment, the above composition has an in vitro dissolution profile of amantadine which shows at least one of (i) not more than 25% dissolution at 2 hours, (ii) not more than 55-85% dissolution at 6 hours, and (iii) at least 80% dissolution at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In a more specific embodiment two of criteria (i), (ii) and (iii) are met. In a more specific embodiment, all three of criteria (i), (ii) and (iii) are met.

In one embodiment, the plasticizer is selected from the group consisting of medium chain triglycerides, diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides, and castor oil. In a more specific embodiment, the plasticizer is medium chain triglycerides, e.g. Miglyol 812 N.

In another aspect, the present invention provides method of administering amantadine, or a pharmaceutically acceptable salt thereof, to a human subject in need thereof, said method comprising orally administering a composition of any of the above aspects.

In another aspect, the present invention provides a method of treating Parkinson's disease in a human subject in need thereof, said method comprising orally administering a composition of any of the above aspects. In a preferred aspect, the present invention provides a method of treating disease in a human subject in need thereof, said method comprising orally administering a composition of any of the above aspects once daily at nighttime, administering 1, 2 or 3 capsules.

References to administering amantadine to a subject in need thereof include treating a patient with a disease or condition which may be treated, prevented or cured by a NMDA antagonist. More specifically, administering amantadine to a subject in need thereof includes treating a patient with Parkinson's Disease, brain injury, brain trauma, dementia, Alzheimer's disease, stroke, Huntington's disease, ALS, Multiple Sclerosis, neurodegenerative diseases, dementias, cerebrovascular conditions, movement disorders, cranial nerve disorders, neuropsychiatric disorders.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the dissolution profiles for three amantadine ER formulations, A, B, C referred to in Example 3.

FIGS. 2A and 2B show the mean plasma concentration-time curves after administration of amantadine IR twice daily (A) and amantadine ER once daily (B) to healthy, adult, male and female subjects under fasting conditions on days 1 and 9.

FIG. 3 shows a plot of mean plasma concentration of amantadine versus time curves after administration of amantadine IR twice daily and amantadine ER once daily to healthy, adult, male and female subjects under fasting conditions on day 9.

FIG. 4 shows the simulated mean plasma concentration of amantadine versus time curves following multiple dose administration of various strengths of immediate release amantadine dosed twice or thrice daily and various strengths of amantadine ER administered once daily.

FIG. 5 shows a plot of mean (SD) plasma amantadine concentrations versus scheduled time for four (4) amantadine treatments.

FIG. 6 shows a semi-logarithmic mean (SD) plasma amantadine concentrations versus scheduled time for four (4) amantadine treatments.

FIG. 7 shows simulated steady state plasma concentration time profiles for the ER amantadine formulations as described in Example 12. The ER amantadine formulation 2, administered once daily at night, results at steady state in about 4 hour delay in achieving peak plasma concentration relative to formulation 1.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a method of reducing sleep disturbances in a patient undergoing treatment with amantadine. The method comprises administering amantadine to a patient in need thereof, such that the amantadine does not interfere with sleep, yet provides maximum benefit in morning hours when often needed most by many patients who take amantadine and further, provides nighttime coverage of symptoms of Parkinson's disease if needed. Nighttime coverage includes providing benefit if the patient wakes up and wishes to return to sleep.

The method of the invention comprises orally administering to the patient an extended release (ER) amantadine composition designed for nighttime administration. The composition is taken less than three hours before bedtime, and preferably less than two and a half, less than two, less than one and a half, or less than one hour before bedtime. Most preferably the ER amantadine composition is taken less than half hour before bedtime (i.e. the time at which the subject wishes to go to sleep for the night). As used herein, a reference to amantadine is intended to encompass pharmaceutically acceptable salts thereof (e.g. amantadine hydrochloride, amantadine sulfate, etc.). Alternatively, the composition is administered less than about 4 hours before bedtime.

As used herein, “extended release” includes “controlled release”, “modified release”, “sustained release”, “timed release”, “delayed release”, and also mixtures of delayed release, immediate release, enteric coated, etc. with each of the above.

The patient may be diagnosed with any disease or disorder for which amantadine is prescribed, such as Parkinson's disease, multiple sclerosis, drug-induced extrapyramidal reactions, levodopa-induced dyskinesia, and viral diseases (e.g. influenza, HBV, and HCV). In a specific embodiment, the patient has Parkinson's disease, which, as used herein, also encompasses a diagnosis of parkinsonism. In one embodiment, the patient has early stage Parkinson's disease, and the amantadine is used as a monotherapy or in combination with a monoamine oxidase type B (MAO-B) inhibitor without concomitant use of levodopa. In another embodiment, the patient has late stage Parkinson's disease and the patient takes levodopa in addition to the amantadine. In another embodiment, the patient has multiple sclerosis and the amantadine is used for the treatment of fatigue. In other embodiments, the patient has a brain injury, brain injury, brain trauma, dementia, Alzheimer's disease, stroke, Huntington's disease, ALS, Multiple Sclerosis, neurodegenerative diseases, dementias, cerebrovascular conditions, movement disorders, cranial nerve disorders, neuropsychiatric disorders.

An ER amantadine composition for use in the invention is adapted for nighttime administration by providing a plasma concentration profile that does not interfere with the subject's sleep. The composition of the invention will, upon administration to a human subject, result in a gradual initial increase in plasma concentration of amantadine such that, at steady state conditions, administration of a dose of the composition results in an increase in plasma concentration of amantadine of less than 25% at three hours after the dose is administered. For example, if a subject's steady state plasma concentration of amantadine is 500 ng/ml at the time a dose of the composition is administered, three hours later the subject's plasma concentration of amantadine will be less than 625 ng/ml. Preferably, the increase in plasma concentration of amantadine is less than 15%, and most preferably, less than 10%. Particularly preferred compositions have a plasma concentration profile further characterized by no increase in amantadine plasma concentration, or even a decrease (at steady state conditions), for at least one or, in a preferred embodiment, two hours after the administration. The composition for use in the invention is further adapted for bedtime (i.e. the time at which the subject wishes to go to sleep for the night) administration by providing a maximum concentration of amantadine (Cmax) in the morning hours. The time to reach Cmax (Tmax), as measured after single dose administration in the fasted state, is at least, 8 hours and up to 13, 14, 15, or 16 hours, or at least 9 hours and up to 13, 14, 15, or 16 hours, or at least 10 hours, and up to 13, 14, 15, or 16 hours. In specific embodiments, the Tmax is 9 to 15 hours, preferably 10 to 14 hours, and most preferably 11 to 13 hours. At steady state, with once daily administration of the composition, the Tmax is 7 to 13 hours, preferably 8 to 12 hours, and most preferably 9 to 11 hours. A suitable ER amantadine composition may be further characterized by having a steady-state Cmax/Cmin ratio of 1.5 to 2.0, and preferably 1.7 to 1.9, resulting in a composition with optimal fluctuation.

In more specific, preferred embodiments, the plasma concentration profile is further characterized by having an AUC profile after administration of a single dose of the composition characterized by: a fractional AUC from 0 to 4 hours that is less than 5%, and preferably less than 3% of AUC_(0-inf); a fractional AUC from 0 to 8 hours that is about 5 to 15%, and preferably about 8 to 12% of AUC_(0-inf); a fractional AUC from 0 to 12 hours that is about 10 to 40%, and preferably about 15 to 30% of AUC_(0-inf); a fractional AUC from 0 to 18 hours that is about 25 to 60%, and preferably about 30 to 50% of AUC_(0-inf); and a fractional AUC from 0 to 24 hours that is about 40 to 75%, and preferably about 50 to 70% of AUC_(0-inf).

In a further preferred embodiment, the plasma concentration profile is further characterized by having an AUC profile after once daily dosing of the composition at steady state conditions characterized by: a fractional AUC from 0 to 4 hours that is about 2 to 25%, and preferably about 5 to 20% of AUC₂₄; a fractional AUC from 0 to 8 hours that is about 15 to 50%, and preferably about 20 to 40% of AUC₂₄; a fractional AUC from 0 to 12 hours that is about 30 to 70%, and preferably about 40 to 60% of AUC₂₄: and a fractional AUC from 0 to 18 hours that is about 60 to 95%, and preferably about 75 to 90% of AUC₂₄.

In some embodiments of any of the above aspects, the steady state plasma concentration profile following multiple administrations to a human subject of the composition at bedtime is characterized by an average plasma concentration during the day (“C-ave-day”, defined as the average day time amantadine plasma concentration as measured in a human PK study) that is 1.1 to 2.0 times the average plasma concentration during the night (“C-ave-night”, defined as the average night time amantadine plasma concentration as measured in a human PK study). In some embodiments, the ratio of C-ave-day/C-ave-night at steady state is within one of the ranges 1.1 to 1.9, 1.1 to 1.8, 1.1 to 1.7, 1.1 to 1.6, 1.1 to 1.5, 1.1 to 1.4, 1.2 to 1.9, 1.2 to 1.7, 1.2 to 1.6, 1.2 to 1.5, 1.3 to 1.9, 1.3 to 1.8, 1.3 to 1.7, 1.3 to 1.6, 1.4 to 1.9, 1.4 to 1.8, 1.4 to 1.7, 1.5 to 1.9, 1.5 to 1.8, 1.5 to 1.7, 1.6 to 1.9, 1.6 to 1.8 or 1.7 to 1.9. In some embodiments, the ratio of C-ave-day/C-ave-night at steady state is 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, or 2.0. In some embodiments, the C-ave-day is the average amantadine plasma concentration as measured between the hours of 5 am, 6 am, 7 am, 8 am or 9 am to the hours of 4 pm, 5 pm, 6 pm, 7 pm or 8 pm and the C-ave-night is the average amantadine plasma concentration as measured between the hours of 4 pm, 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm or 11 pm to the hours of 5 am, 6 am, 7 am, 8 am or 9 am. In some embodiments, the C-ave-day is the average amantadine plasma concentration as measured within any four to twelve hour period between the hours of 5 am and 8 pm; and the C-ave-night is the average amantadine plasma concentration as measured within any four to twelve hour period between the hours of 8 pm and 5 am. In some embodiments, the C-ave-day is the average amantadine plasma concentration as measured within any four, five, six, seven, eight, nine, ten, eleven or twelve hour period between the hours of 5 am and 8 pm; and the C-ave-night is the average amantadine plasma concentration as measured within any four, five, six, seven, eight, nine, ten, eleven or twelve hour period between the hours of 8 pm and 5 am.

In some embodiments described herein an amantadine composition is administered to a patient from 0 to 4 hours prior to bedtime. In some embodiments, the amantadine composition is administered to a patient from 0 to 3, 0 to 2 or 0 to 1 hours prior to bedtime. In some embodiments, the amantadine composition is administered to a patient from 0 to 240 minutes, from 0 to 180 minutes, e.g. from 0 to 120 minutes, from 0 to 60 minutes, from 0 to 45 minutes, from 0 to 30 minutes, from 0 to 15 minutes or from 0 to 10 minutes prior to bedtime. In some embodiments, the amantadine composition is administered to a patient from 60 to 240 minutes, from 60 to 180 minutes, from 60 to 120 minutes or from 60 to 90 minutes prior to bedtime.

It is to be understood that administration to a patient includes administration by a healthcare professional and self administration by the patient.

Unless otherwise specified herein, the term “bedtime” has the normal meaning of a time when a person retires for the primary sleep period during a twenty-four hour period of time. While for the general populace, bedtime occurs at night, there are patients, such as those who work nights, for whom bedtime occurs during the day. Thus, in some embodiments, bedtime may be anytime during the day or night.

As used herein, unless otherwise indicated, reference to a plasma concentration profile or a specific pharmacokinetic property (e.g. Cmax, Cmin, AUC, Tmax, etc.) in a human subject refers to a mean value obtained from healthy adults s determined in a typical phase I clinical trial designed to measure pharmacokinetic properties of a drug (see e.g. Examples 5, 6 and 7, below). References herein to Tmax refer to values obtained after administration of a single dose at fasted states, unless otherwise indicated.

In some embodiments of the invention, the dose of the amantadine administered in accordance with the present invention is within or above the ranges normally prescribed for immediate release compositions of amantadine. In other embodiments, the doses of the amantadine administered with the present invention are higher than the ranges normally prescribed for immediate release compositions of amantadine. For example, the recommended dose of amantadine for the treatment of Parkinson's disease is 100 mg administered twice daily. In limited cases of the patient not deriving sufficient benefit at that dose and subject to the patient being able to tolerate such higher dose, the dose may be increased to 300 mg or 400 mg in divided doses. The most commonly prescribed doses of amantadine are 100 mg to 200 mg per day, with the latter administered in divided doses. More than 200 mg (for example 300 mg) is always given in divided doses. For the present invention, doses of 50 to 600 mg, or more preferably, 200 to 450 mg are administered for treatment of Parkinson's disease, and the methods and compositions of the invention may comprise administration of a dose as defined by any of these ranges. In specific embodiments the administration of such higher doses may be once daily. In additional embodiments the administration of such higher doses may be at night. In additional embodiments the administration of such higher doses may be in the form of 1, 2 or 3 capsules of size 0, 1 or 2 administered once daily.

In one embodiment of any of the above aspects the amantadine is administered as a pharmaceutically acceptable salt. In a more specific embodiment, the amantadine is administered as hydrochloride or amantadine sulfate.

In one embodiment of any of the above aspects, a total daily dose of 50 mg to 600 mg of amantadine, or a pharmaceutically acceptable salt thereof is administered to a patient. More specifically the daily dose of amantadine or pharmaceutically acceptable salt thereof administered may be in the range of 100 mg to 440 mg. In another specific embodiment, the daily dose of amantadine or pharmaceutically acceptable salt thereof maybe in the range of 260 mg to 420 mg. In another embodiment, the daily dose of amantadine or pharmaceutically acceptable salt thereof administered exceeds 300 mg per day. In various specific embodiments, the daily dose of amantadine or pharmaceutically acceptable salt thereof may be 50 to 75 mg, 70 to 95 mg, 90 to 115 mg, 110 to 135 mg, 130 to 155 mg, 150 to 175 mg, 170 to 195 mg, 190 to 215 mg, 210 to 235 mg, 230 to 255 mg, 250 to 275 mg, 270 to 295 mg, 290 to 305 mg, 300 to 315 mg, 310 to 325 mg, 320 to 335 mg, 330 to 345 mg, 340 to 355 mg, 350 to 365 mg, 360 to 375 mg, 370 to 385 mg, 380 to 395 mg, 390 to 405 mg, 400 to 415 mg, 410 to 425 mg, 420 to 435 mg, 430 to 445 mg or 440 to 455 mg.

In one embodiment of any of the above aspects, the composition comprises 50 to 600 mg of amantadine, or a pharmaceutically acceptable salt thereof. More specifically, the composition may comprise 100 to 450 mg of amantadine, or a pharmaceutically acceptable salt thereof. Still more specifically, the composition may comprise 130-210 mg of amantadine, or a pharmaceutically acceptable salt thereof. In various specific embodiments, the dosage form comprises 50 to 75 mg, 70 to 95 mg, 90 to 115 mg, 110 to 135 mg, 130 to 155 mg, 150 to 175 mg, 170 to 195 mg, 190 to 215 mg, 210 to 235 mg, 230 to 255 mg, 250 to 275 mg, 270 to 295 mg, 290 to 305 mg, 300 to 315 mg, 310 to 325 mg, 320 to 335 mg, 330 to 345 mg, 340 to 355 mg, 350 to 365 mg, 360 to 375 mg, 370 to 385 mg, 380 to 395 mg, 390 to 405 mg, 400 to 415 mg, 410 to 425 mg, 420 to 435 mg, 430 to 445 mg or 440 to 455 mg of amantadine, or a pharmaceutically acceptable salt thereof. In a more specific embodiment, the composition comprises about 110, 120, 130, 140, 150, 160 170, 180, 190, 210, or 220 mg amantadine, or a pharmaceutically acceptable salt thereof. In another more specific embodiment, the composition comprises 110 mg amantadine hydrochloride. In another more specific embodiment, the composition comprises 130 mg amantadine hydrochloride. In another more specific embodiment, the composition comprises 170 mg amantadine hydrochloride. In another more specific embodiment, the composition comprises 210 mg amantadine hydrochloride.

In one embodiment of any of the above aspects, the composition comprises from about 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, 110 mg, 120 mg, 130 mg, 140 mg, 150 mg, 160 mg, 170 mg, 180 mg, 190 mg, 200 mg, 210 mg, 220 mg, 230 mg, 240 mg, 250 mg, 260 mg of amantadine, or a pharmaceutically acceptable salt thereof to about 75 mg, 85 mg, 95 mg, 105 mg, 115 mg, 125 mg, 135 mg, 145 mg, 155 mg, 165 mg, 175 mg, 185 mg, 195 mg, 205 mg, 215 mg, 225 mg, 235 mg, 245 mg, 255 mg, 265 mg, 275 mg, 285 mg, 295 mg, 305 mg, 315 mg, 325 mg, 335 mg, 345 mg, 355 mg, 365 mg, 375 mg, 385 mg, 395 mg, 405 mg, 415 mg, 425 mg, 435 mg, 445 mg of amantadine, or a pharmaceutically acceptable salt thereof.

In a specific embodiment of the invention, a subject's entire daily dose of amantadine is administered once, during a period of less than about three, two or one hours before bedtime (i.e. the time at which the subject wishes to go to sleep for the night). In other embodiments, at least one half of the daily dose of amantadine is taken during said period before bedtime. Preferably at least ⅔ of the dose of amantadine is taken in said period before bedtime, with the remainder taken in morning or afternoon. The morning or afternoon dose of the amantadine may be provided in a conventional, immediate release dosage form, or in an extended release form.

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in levodopa induced dyskinesia. In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80% reduction in levodopa induced dyskinesia. In further embodiments, the reduction in levodopa induced dyskinesia is measured on a numeric scale that is used by or accepted by the FDA or other regulatory agencies to evaluate the effectiveness of and to approve for licensure drugs for the treatment of LID. In further specific embodiments, the scale used in measuring the reduction in LID could be UDysRS, UPDRS Part IV (subscores 32, 33), Dyskinesia Rating Scale (DRS), Abnormal Involuntary Movement Scale (AIMS), Rush Dyskinesia Rating Scale, Parkinson Disease Dyskinesia Scale (PDYS-26), Obeso Dyskinesia Rating Scale (CAPIT), Clinical Dyskinesia Rating Scale (CDRS), Lang-Fahn Activities of Daily Living Dyskinesia or other scales developed for this purpose.

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in Parkinson's disease fatigue. In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60% reduction in Parkinson's disease fatigue. In further specific embodiments, the reduction in fatigue is measured on a numerical scale used by or accepted by the FDA or other regulatory agencies to evaluate the effectiveness of and to approve for licensure drugs for the treatment of fatigue. In further specific embodiments, the scale used in measuring the reduction in fatigue could be the Fatigue Severity Scale (FSS), Fatigue Assessment Inventory, Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT Fatigue), Multidimensional Fatigue Inventory (MFI-20), Parkinson Fatigue Scale (PFS-16) and the Fatigue Severity Inventory. In other specific embodiments, the reduction in fatigue is measured relative to placebo in a controlled clinical trial. In other embodiments, the reduction in fatigue is measured relative to baseline in a controlled clinical trial.

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in Parkinson's disease symptoms. In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40% reduction in Parkinson's symptoms. In further specific embodiments, the reduction in Parkinson's symptoms is measured on a numerical scale used by or accepted by the FDA or other regulatory agencies to evaluate the effectiveness of and to approve for licensure drugs for the treatment of Parkinson's symptoms. In further specific embodiments, the scale used in measuring the reduction in Parkinson's symptoms could be the Unified Parkinson's Disease Rating Scale (UPDRS). Unified Parkinson's Disease Rating Scale (UPDRS, MDS revision)—Part I: non-motor aspects of experiences of daily living (13 items), Part II: motor aspects of experiences of daily living (13 items)—Part III: motor examination (33 scored items)—Part I: mental status, behavior and mood—Part II: activities of daily living—Part III: motor examination (27 scored items) Hoehn and Yahr Staging Scale (Original or Modified).

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in levodopa induced dyskinesia. In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80% reduction in levodopa induced dyskinesia. In further embodiments, the reduction in levodopa induced dyskinesia is measured on a numeric scale that is used by the FDA to evaluate effectiveness of drugs indicated to reduce LID. In further specific embodiments, the scale used in measuring the reduction in LID could be UDysRS, UPDRS Part IV (subscores 32, 33), Dyskinesia Rating Scale (DRS), Abnormal Involuntary Movement Scale (AIMS), or other scales developed for this purpose. In other specific embodiments, the reduction in LID is measured relative to placebo in a controlled clinical trial. In other embodiments, the reduction in LID is measured relative to baseline in a controlled clinical trial.

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in Parkinson's disease fatigue. In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40% reduction in Parkinson's disease fatigue. In further specific embodiments, the reduction fatigue is measured on a numeric scale that is used by the FDA to evaluate effectiveness of drugs indicated to reduce fatigue. In further specific embodiments, the scale used in measuring the reduction in fatigue could be the Fatigue Severity Scale (FSS). In other specific embodiments, the reduction in fatigue is measured relative to placebo in a controlled clinical trial. In other embodiments, the reduction in fatigue is measured relative to baseline in a controlled clinical trial.

In one embodiment of any of the above aspects, administration of the composition to a Parkinson's disease patients results in a significant reduction in Parkinson's disease symptoms. In a specific embodiment, administration of the composition results in about 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40% reduction in Parkinson's symptoms. In further specific embodiments, the reduction in Parkinson's symptoms is measured on a numeric scale that is used by the FDA to evaluate effectiveness of drugs indicated to reduce Parkinson's symptoms. In further specific embodiments, the scale used in measuring the reduction in Parkinson's symptoms could be the Unified Parkinson's Disease Rating Scale (UPDRS). In other specific embodiments, the reduction in Parkinson's disease symptoms is measured relative to placebo in a controlled clinical trial. In other embodiments, the reduction in Parkinson's disease symptoms is measured relative to baseline in a controlled clinical trial.

Extended Release Formulations

Extended release amantadine compositions suitable for use in the method of the invention can be made using a variety of extended release technologies, such as those described in the patent publications referenced in the above background section, which publications are incorporated herein by reference in their entireties. In some embodiments, the invention is a pellet in capsule dosage form. In some embodiments, the pellets comprise a pellet core, which is coated with at least one drug layer and at least one extended release coating layer. In some embodiments, the pellets are coated with at least one drug layer, an intermediate layer such as a seal coat and an extended release coating layer. In some embodiments, the pellet, the drug layer or both comprise one or more binders.

In some embodiments, the dosage unit comprises a plurality of coated pellets. In some embodiments, the pellets have a diameter of for example 300 to 1700 microns, in some cases 500 to 1200 microns. The pellets will comprise, for example, inert substrates, such as sugar spheres, microcrystalline cellulose (MCC) spheres, starch pellets. In some embodiments, pellets can be prepared by other processes such as pelletization, extrusion, spheronization, etc. or combinations thereof. The core pellets will comprise of amantadine hydrochloride and pharmaceutically acceptable excipients.

Coated Pellets

The pellet cores are coated with the active ingredient, e.g., amantadine or a pharmaceutically acceptable salt and/or polymorph thereof. In some embodiments, in addition to the active ingredient, the pellets also comprise one or more binders, such as for example hydroxypropyl methyl cellulose, copovidone, povidone, hydroxypropyl cellulose, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose etc. In some embodiments, the pellets also contain one or more additional excipients, such as anti-tack agents (e.g. talc, magnesium stearate etc.)

In some embodiments, the pellets cores are coated with a drug layer comprising active ingredient, and optionally one or more binders, anti-tack agents and/or solvents by conventional coating techniques such as fluidized bed coating, pan coating.

Intermediate Layer Coating

In some embodiments, the pellets are coated with an intermediate layer, such as a seal coat. In some embodiments, the seal coat is adapted to prevent ingredients in the extended release coating from interacting with ingredients in the pellet core, to prevent migration of the ingredients in the pellet core from diffusing out of the pellet core into the extended release layer, etc. As described herein, the seal coat of the present invention can comprise one or more film forming polymers including but not limited to hydroxypropylmethyl cellulose (HPMC), copovidone, povidone, polyvinyl pyrrolidone, hydroxypropyl cellulose, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose or any combination thereof and the like.

The seal coat can further comprise other additives like plasticizers, such as, propylene glycol, triacetin, polyethylene glycol, tributyl citrate and optionally anti-tacking agents, such as, magnesium stearate, calcium silicate, magnesium silicate, and colloidal silicon dioxide or talc.

Apart from plasticizers and anti-tacking agents as mentioned above, the seal coat can optionally contain buffers, colorants, opacifiers, surfactants or bases, which are known to those skilled in the art.

Seal coating can be applied to the core using conventional coating techniques such as fluidized bed coating, pan coating etc. In some embodiments, the drug coated pellets cores are coated with a seal coat layer that optionally comprises one or more binders, anti-tack agents and/or solvents by fluidized bed coating or pan coating.

Binders

In some embodiments, either the pellet cores, the intermediate coating layer, or both may comprise one or more binders (e.g., film forming polymers). Suitable binders for use herein include, e.g.: alginic acid and salts thereof; cellulose derivatives such as carboxymethylcellulose, methylcellulose (e.g., Methocel®), hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose (e.g., Klucel®), ethylcellulose (e.g., Ethocel®), and microcrystalline cellulose (e.g., Avicel®); microcrystalline dextrose; amylose; magnesium aluminum silicate; polysaccharide acids; bentonites; gelatin; polyvinylpyrrolidone/vinyl acetate copolymer; crospovidone; povidone; starch; pregelatinized starch; tragacanth, dextrin, a sugar, such as sucrose (e.g., Dipac®), glucose, dextrose, molasses, mannitol, sorbitol, xylitol (e.g., Xylitab®), and lactose; a natural or synthetic gum such as acacia, tragacanth, ghatti gum, mucilage of isapol husks, polyvinylpyrrolidone (e.g., Polyvidone® CL, Kollidon® CL, Polyplasdone® XL-10), larch arabogalactan, Veegum®, polyethylene glycol, waxes, sodium alginate, and the like.

Extended Release Coating

The pellets are coated with an extended release coating. The extended release coating is adapted to delay release of the drug from the coated drug cores for a period of time after introduction of the dosage form into the use environment. In some embodiments, the extended release coating includes one or more pH-dependent or non-pH-dependent extended release excipients. Examples of non-pH dependent extended release polymers include ethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, copolymer of ethyl acrylate, methyl methacrylate (e.g. Eudgrait RS) etc. Examples of pH dependent extended release excipients include methacrylic acic copolymers, hydroxypropylmethyl cellulose acetate succinate, hydroxypropylmethyl cellulose phthalate, and cellulose acetate phthalate etc. The extended release coating may also include a pore former, such as povidone, polyethylene glycol, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, etc., sugars such as sucrose, mannitol, lactose, and salts, such as sodium chloride, sodium citrate, etc., a plasticizer, such as acetylated citrated esters, acetylated glycerides, castor oil, citrate esters, dibutylsebacate, glyceryl monostearate, diethyl phthalate, glycerol, medium chain triglycerides, propylene glycol, polyethylene glycol. The extended release coating may also include one or more additional excipients, such as lubricants (e.g., magnesium stearate, talc etc.).

Extended release coating can be applied using conventional coating techniques such as fluidized bed coating, pan coating etc. The drug coated pellets cores, which optionally comprise a seal coat, are coated with the extended release coating by fluidized bed coating.

Extended Release Excipients (Coating Polymers)

As described herein, exemplary extended release excipients include, but are not limited to, insoluble plastics, hydrophilic polymers, and fatty compounds. Plastic matrices include, but are not limited to, methyl acrylate-methyl methacrylate, polyvinyl chloride, and polyethylene. Hydrophilic polymers include, but are not limited to, cellulosic polymers such as methyl and ethyl cellulose, hydroxyalkyl celluloses such as hydroxypropyl cellulose, hydroxypropylmethyl cellulose, sodium carboxymethyl cellulose, and cross-linked acrylic acid polymers like Carbopol® 934, polyethylene oxides and mixtures thereof. Fatty compounds include, but are not limited to, various waxes such as carnauba wax and glyceryl tristearate and wax-type substances including hydrogenated castor oil or hydrogenated vegetable oil, or mixtures thereof.

In certain embodiments, the plastic material can be a pharmaceutically acceptable acrylic polymer, including but not limited to, acrylic acid and methacrylic acid copolymers, methyl methacrylate, methyl methacrylate copolymers, ethoxyethyl methacrylates, cyanoethyl methacrylate, aminoalkyl methacrylate copolymer, poly(acrylic acid), poly(methacrylic acid), methacrylic acid alkylamine copolymer poly(methyl methacrylate), poly(methacrylic acid)(anhydride), polymethacrylate, polyacrylamide, poly(methacrylic acid anhydride), and glycidyl methacrylate copolymers.

In certain other embodiments, the acrylic polymer is comprised of one or more ammonio methacrylate copolymers. Ammonio methacrylate copolymers are well known in the art, and are described in NF XVII as fully polymerized copolymers of acrylic and methacrylic acid esters with a low content of quaternary ammonium groups.

In still other embodiments, the acrylic polymer is an acrylic resin lacquer such as that which is commercially available from Rohm Pharma under the trade name Eudragit®. In further embodiments, the acrylic polymer comprises a mixture of two acrylic resin lacquers commercially available from Rohm Pharma under the trade names Eudragit® RL30D and Eudragit® RS30D, respectively. Eudragit® RL30D and Eudragit® RS30D are copolymers of acrylic and methacrylic esters with a low content of quaternary ammonium groups, the molar ratio of ammonium groups to the remaining neutral (meth)acrylic esters being 1:20 in Eudragit RL30D and 1:40 in Eudragit® RS30D. The mean molecular weight is about 150,000. Edragit® S-100 and Eudragit® L-100 are also suitable for use herein. The code designations RL (high permeability) and RS (low permeability) refer to the permeability properties of these agents. Eudragit® RL/RS mixtures are insoluble in water and in digestive fluids. However, multiparticulate systems formed to include the same are swellable and permeable in aqueous solutions and digestive fluids.

The polymers described above such as Eudragit® RL/RS may be mixed together in any desired ratio in order to ultimately obtain an extended release formulation having a desirable dissolution profile. One skilled in the art will recognize that other acrylic polymers may also be used, such as, for example, Eudragit® L.

Pore Formers

In some embodiments, the extended release coating includes a pore former. Pore formers suitable for use in the extended release coating can be organic or inorganic agents, and include materials that can be dissolved, extracted or leached from the coating in the environment of use. Examples of pore formers include but are not limited to organic compounds such as mono-, oligo-, and polysaccharides including sucrose, glucose, fructose, mannitol, mannose, galactose, lactose, sorbitol, pullulan, dextran; polymers soluble in the environment of use such as water-soluble hydrophilic polymers, such as povidone, crospovidone, polyethylene glycol, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, hydroxyalkyl celluloses, carboxyalkyl celluloses, cellulose ethers, acrylic resins, polyvinylpyrrolidone, cross-linked polyvinylpyrrolidone, polyethylene oxide, carbowaxes, Carbopol®, and the like, diols, polyols, polyhydric alcohols, polyalkylene glycols, polyethylene glycols, polypropylene glycols, or block polymers thereof, polyglycols, poly(α-Ω)alkylenediols; inorganic compounds such as alkali metal salts, lithium carbonate, sodium chloride, sodium bromide, potassium chloride, potassium sulfate, potassium phosphate, sodium acetate, sodium citrate, suitable calcium salts, and the like. In certain embodiments, plasticizers can also be used as a pore former.

Capsules

The extended release pellets are introduced into a suitable capsule by using an encapsulator equipped with pellet dosing chamber. The capsule sizes may be 00, 0, 0EL, 1, 1EL, 2, 2EL, 3, 4 or 5. A particularly preferred composition that provides ideal pharmacokinetic properties and plasma concentration profiles is a pellet-in-capsule composition that comprises a plurality of pellets, typically having a diameter of about 500 μm to 1.2 mm, and preferably about 700 μm to 1000 μm, where each pellet comprises a core comprising amantadine and a binder, and an extended release coating surrounding the core that extends release of the amantadine so as to provide the desired pharmacokinetic properties and amantadine plasma concentration profiles described above.

In some embodiments, the pellets in the pellet-in-capsule are in a size 0 or smaller, preferably a size 1 or smaller capsule. Mean pellet diameters in some embodiments may be in a range of 500 μm to 1200 μm, e.g. from 500 μm to 1100 μm, from 500 μm to 1000 μm, from 500 μm to 900 μm, from 500 μm to 800 μm, from 500 μm to 700 μm, from 600 μm to 1100 μm, from 600 μm to 1000 μm, from 600 μm to 900 μm, from 600 μm to 800 μm, from 600 μm to 700 μm, from 700 μm to 1100 μm, from 700 μm to 1000 μm, from 700 μm to 900 μm, or from 700 μm to 800 μm. In some embodiments the mean particle diameters are, ±10%, e.g.: 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 1000 μm, 1050 μm, 1100 μm, 1150 μm or 1200 μm.

One preferred composition of the invention is a pellet-in-capsule composition wherein each pellet comprises a core that comprises a core seed with a mixture of amantadine and a binder coated onto the core seed, and an extended release coating surrounding the core comprising ethyl cellulose, a pore forming agent such as hydroxypropyl methyl cellulose or povidone, and a plasticizer. In some embodiments, the pellets may further comprise a seal coating between the pellet core and the extended release coating. The pellets are formulated using methods known in the art, such as those described in Example 1 below. In a specific embodiment, based on the combined weight of the pellet core and extended release coating, the amantadine is present in amounts from 20-80 wt %, 45-70 wt %, 40-50 wt %, 45-55 wt %, 50-60 wt %, 55-65 wt %, 60-70 wt %, 65-75 wt %, 70-80 wt %, or 40 to 60 wt %, the binder, which is preferably hydroxypropyl methyl cellulose, copovidone, or mixtures thereof, is present in amounts from 1 to 25 wt %, the core seed, preferably a sugar sphere (nonpareil) or microcrystalline cellulose seed (e.g. Celphere®), is present in amounts from 8 to 25 wt %, the ethyl cellulose is present in amounts from 10 to 20 wt %, the pore forming agent, preferably povidone, is present in amounts from 1 to 4 wt %, and the plasticizer is present in amounts from 1 to 4 wt %. In another specific embodiment, based on the combined weight of the pellet core and extended release coating, the amantadine is present in amounts from 50 to 70 wt %, the binder, which is preferably hydroxypropyl methyl cellulose, copovidone, or mixtures thereof, is present in amounts from 1 to 25 wt %, the core seed, preferably a sugar sphere (nonpareil) or microcrystalline cellulose seed (e.g. Celphere®), is present in amounts from 5 to 15 wt %, the ethyl cellulose is present in amounts from 1 to 15 wt %, the pore forming agent, preferably povidone, is present in amounts from 0.25 to 4 wt %, and the plasticizer is present in amounts from 0.25 to 4 wt %.

Additional embodiments of the invention are illustrated in the Table, below, entitled “Various Amantadine ER Capsule Size 1 Formulations”. By means of methods and compositions described herein, formulations can be made that achieve the desired dissolution characteristics and target pharmacokinetic profiles described herein. More specifically, therapeutically effective doses of amantadine can be administered once daily in no more than two size 1 (or smaller, e.g. size 2 or 3) capsules using the manufacturing methods and compositions that have been described herein to achieve these results. In particular, higher drug loading can be achieved using compositions and manufacturing methods described herein. In some embodiments, higher drug loading may be achieved, with the required dissolution profile, using smaller core pellet sizes and concomitantly increased drug layering on smaller cores, but with no change in the extended release coat. In some embodiments, using alternative manufacturing approaches described herein, e.g. extrusion and spheronization, even higher drug loads can be achieved to realize the desired dissolution profile, enabling high amantadine drug loads with suitable pharmacokinetic profiles, resulting in compositions that are therapeutically more effective, and at least as well tolerated, and can be filled in relatively small sized capsules (e.g., size 1, 2 or 3), enabling ease of administration to patients.

TABLE Various Amantadine ER Capsule Size 1 Formulations Inert Core Extended AMT Pellet Active Release Bulk % Fill in AMT Dissolution (%) Strength Manufacture Size Drug Coating % Density Size 1 (at T (hrs)): (mg) Method (mm) % w/w w/w (g/cm³) Capsule 2 hrs 6 hrs 12 hrs 110 mg Fluid bed 0.3-0.5 40-50% 10-30% 0.6-1.0 60-70% <25% 40-80% >80% coating 140 mg Fluid bed 0.3-0.5 45-50% 10-30% 0.6-1.0 80-90% <25% 40-80% >80% coating 150 mg Fluid bed 0.3-0.5 50-55% 10-30% 0.6-1.0 80-90% <25% 40-80% >80% coating 170 mg Fluid bed 0.2-0.3 50-55% 10-30% 0.6-1.0 80-90% <25% 40-80% >80% coating 170 mg Extrusion N/A 55-75% 10-30% 0.6-1.0 65-75% <25% >80% spheronization, pan or fluidized bed coating 190 mg Extrusion N/A 55-75% 10-30% 0.6-1.0 75-85% <25% 40-80% >80% spheronization, pan or fluidized bed coating 210 mg Extrusion N/A 55-75% 10-30% 0.6-1.0 80-90% <25% 40-80% >80% spheronization, pan or fluidized bed coating 230 mg Extrusion N/A 55-75% 10-30% 0.6-1.0 85-95% <25% 40-80% >80% spheronization, pan or fluidized bed coating

In some embodiment, the amantadine, or a pharmaceutically acceptable salt thereof, is present in amounts from 20 to 80 wt % (based on the combined weight of the pellet core and extended release coating), with a bulk density of 0.3 to 1.2 g/cm³. In some embodiments, the amantadine or pharmaceutically acceptable salt thereof is present in amounts from 20 to 77.5 wt %, from 20 to 75 wt %, from 20 to 72.5 wt %, from 20 to 70 wt %, from 20 to 67.5 wt %, from 20 to 65 wt %, from 20 to 62.5 wt %, from 20 to 60 wt %, from 20 to 57.5 wt %, from 20 to 55 wt %, from 20 to 52.5 wt %, from 20 to 50 wt %, from 20 to 47.5 wt %, from 20 to 45 wt %, from 20 to 42.5 wt %, from 20 to 40 wt %, from 20 to 37.5 wt %, from 20 to 35 wt %, from 20 to 32.5 wt %, from 20 to 30 wt %, from 30 to 80 wt %, from 30 to 77.5 wt %, from 30 to 75 wt %, from 30 to 72.5 wt %, from 30 to 70 wt %, from 30 to 67.5 wt %, from 30 to 65 wt %, from 30 to 62.5 wt %, from 30 to 60 wt %, from 30 to 57.5 wt %, from 30 to 55 wt %, from 30 to 52.5 wt %, from 30 to 50 wt %, from 30 to 47.5 wt %, from 30 to 45 wt %, from 30 to 42.5 wt %, from 30 to 40 wt %, from 40 to 80 wt %, from 40 to 77.5 wt %, from 40 to 75 wt %, from 40 to 72.5 wt %, from 40 to 70 wt %, from 40 to 67.5 wt %, from 40 to 65 wt %, from 40 to 62.5 wt %, from 40 to 60 wt %, from 40 to 57.5 wt %, from 40 to 55 wt %, from 40 to 52.5 wt %, from 40 to 50 wt %, from 40 to 47.5 wt %, from 40 to 45 wt %, from 50 to 80 wt %, from 50 to 77.5 wt %, from 50 to 75 wt %, from 50 to 72.5 wt %, from 50 to 70 wt %, from 50 to 67.5 wt %, from 50 to 65 wt %, from 50 to 62.5 wt %, from 50 to 60 wt %, from 50 to 57.5 wt %, from 50 to 55 wt %, from 60 to 80 wt %, from 60 to 77.5 wt %, from 60 to 75 wt %, from 60 to 72.5 wt %, from 60 to 70 wt %, from 60 to 67.5 wt %, from 60 to 65 wt %. In some embodiments, the bulk density is 0.3 to 1.2 g/cm³, 0.3 to 1.15 g/cm³, 0.3 to 1.1 g/cm³, 0.3 to 1.05 g/cm³, 0.3 to 1.0 g/cm³, 0.3 to 0.9 g/cm³, 0.3 to 0.8 g/cm³, 0.3 to 0.7 g/cm³, 0.3 to 0.6 g/cm³, 0.3 to 0.5 g/cm³, 0.3 to 0.4 g/cm³, 0.4 to 1.2 g/cm³, 0.4 to 1.15 g/cm³, 0.4 to 1.1 g/cm³, 0.4 to 1.05 g/cm³, 0.4 to 1.0 g/cm³, 0.4 to 0.9 g/cm³, 0.4 to 0.8 g/cm³, 0.4 to 0.7 g/cm³, 0.4 to 0.6 g/cm³, 0.4 to 0.5 g/cm³, 0.5 to 1.2 g/cm³, 0.5 to 1.15 g/cm³, 0.5 to 1.1 g/cm³, 0.5 to 1.05 g/cm³, 0.5 to 1.0 g/cm³, 0.5 to 0.9 g/cm³, 0.5 to 0.8 g/cm³, 0.5 to 0.7 g/cm³, 0.5 to 0.6 g/cm³, 0.6 to 1.2 g/cm³, 0.6 to 1.15 g/cm³, 0.6 to 1.1 g/cm³, 0.6 to 1.05 g/cm³, 0.6 to 1.0 g/cm³, 0.6 to 0.9 g/cm³, 0.6 to 0.8 g/cm³, 0.6 to 0.7 g/cm³, 0.7 to 1.2 g/cm³, 0.7 to 1.15 g/cm³, 0.7 to 1.1 g/cm³, 0.7 to 1.05 g/cm³, 0.7 to 1.0 g/cm³, 0.7 to 0.9 g/cm³, 0.7 to 0.8 g/cm³, 0.5 to 1.2 g/cm³, 0.8 to 1.15 g/cm³, 0.8 to 1.1 g/cm³, 0.8 to 1.05 g/cm³, 0.8 to 1.0 g/cm³, 0.8 to 0.9 g/cm³, 0.9 to 1.2 g/cm³, 0.9 to 1.15 g/cm³, 0.9 to 1.1 g/cm³, 0.9 to 1.05 g/cm³, or 0.9 to 1.0 g/cm³. In some embodiments, the composition is in a dosage unit comprising a pellet in capsule formulation, wherein the capsule size is size 00, size 0, size 1, size 2 or size 3. In some preferred embodiments, the dosage unit includes pellets containing from 50 to 250 mg of amantadine in a size 0, 1, 2 or 3 capsule. In some embodiments, the dosage unit includes pellets containing from 100 to 250 mg, e.g. 100 to 200 mg of amantadine in a size 0, 1, 2 or 3 capsule, preferably a size 1, 2 or 3 capsule. In a more specific embodiment, the dosage unit comprises about 110, 120, 130, 140, 150, 160 170, 180, 190, 210, or 220 mg amantadine, or a pharmaceutically acceptable salt thereof. In another more specific embodiment, the dosage unit comprises 110 mg amantadine hydrochloride. In another more specific embodiment, the dosage unit comprises 130 mg amantadine hydrochloride. In another more specific embodiment, the dosage unit comprises 170 mg amantadine hydrochloride. In another more specific embodiment, the dosage unit comprises 210 mg amantadine hydrochloride.

Suitable plasticizers include medium chain triglycerides, diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides, castor oil, and the like. The pellets are filled into capsules to provide the desired strength of amantadine. An advantage of this composition is it provides the desired release properties that make the composition suitable for administration during said period before bedtime. A further advantage is that the extended release coating is sufficiently durable so that the capsule can be opened and the pellets sprinkled onto food for administration to patients who have difficulty swallowing pills, without adversely affecting the release properties of the composition. When the composition is administered by sprinkling onto food, it is preferred to use a soft food such as applesauce or chocolate pudding, which is consumed within 30 minutes, and preferably within 15 minutes. A yet further advantage of the above-described composition is that it has very good batch-to-batch reproducibility and shelf-life stability.

In some embodiments, the composition of the invention has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 55-85% at 6 hours, and at least 80% at 12 hours, as measured using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. More preferably, the in vitro dissolution is further characterized by release of amantadine of not more than 10% at 1 hour, 30-50% at 4 hours, and at least 90% at 12 hours.

In additional embodiments, 110 mg to 210 mg of ER amantadine in a size 1 capsule of the composition of the invention has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 55-85% at 6 hours, and at least 80% at 12 hours, as measured using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. More preferably, the in vitro dissolution is further characterized by release of amantadine of not more than 10% at 1 hour, 30-50% at 4 hours, and at least 90% at 12 hours.

In one embodiment of any of the above aspects the composition has an in vitro dissolution profile of amantadine which shows at least one of (i) not more than 25% dissolution at 2 hours, (ii) not more than 25-55% dissolution at 6 hours, and (iii) at least 80% dissolution at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In a more specific embodiment two of criteria (i), (ii) and (iii) are met. In a more specific embodiment, all three of criteria (i), (ii) and (iii) are met.

In one embodiment of any of the above aspects the composition has an in vitro dissolution profile of amantadine which shows at least one of (i) not more than 20% dissolution at 1 hour, (ii) about 25-45% dissolution at 2 hours, (iii) not more than 50-80% dissolution at 4 hours, and (iii) at least 80% dissolution at 8 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In a more specific embodiment two of criteria (i), (ii) and (iii) are met. In a more specific embodiment, all three of criteria (i), (ii) and (iii) are met.

A preferred pellet-in-capsule compostion of the invention, in addition to having the above in vitro dissolution properties and any of the above-described pharmacokinetic properties (e.g. in vivo release profile, Tmax, Cmax/Cmin ratio, etc) that make the composition suitable for administration in said period before bedtime. The composition is further characterized by providing a Cmax of 1.6-2.4 ng/ml per mg of amantadine and an AUC_(0-inf) of 40-75 ng*h/mL per mg of amantadine after oral administration of a single dose of the capsule to a human subject in a fasted state. A preferred pellet-in-capsule composition is further characterized by a steady state plasma concentration in which once daily oral administration of the capsule to a human subject provides a Cmax of 2.4 to 4.2 ng/ml per mg of amantadine, a Cmin of 1.1 to 2.6 ng/ml per mg of amantadine, and an AUC₀₋₂₄ of 48-73 ng*h/mL per mg of amantadine.

The above-described pellet-in-capsule compositions may be provided at a strength suitable for amantadine therapy. Typical strengths range from at least about 50 mg to about 250 mg. In a specific embodiment, the capsule strength is 70 mg, 80 mg, 90 mg, 110 mg, 120 mg, 125 mg, 130 mg, 140 mg, 150 mg, 160 mg, 160mg, 170 mg, 180 mg, 190 mg, 210 mg, and 220 mg, that provides a single dose AUC_(0-inf) per mg that is equivalent to a 100 mg tablet of an immediate release formulation of amantadine HCl (e.g. Symmetrel®, or other FDA Orange Book reference listed drug). One, two, or three, of such capsules can be administered to a subject in the period before bedtime. In a preferred embodiment, between 220 mg and 650 mg of amantadine is administered using 2 capsules of a suitable ER formulations once daily.

The invention may also be described in terms of the following numbered embodiments:

-   1. An extended release (ER) composition comprising amantadine, or a     pharmaceutically acceptable salt thereof, for use in a method of     administering amantadine to a subject in need thereof, said method     comprising orally administering said composition less than three     hours before bedtime (i.e. the time at which the subject wishes to     go to sleep for the night). -   2. Use of amantadine, or a pharmaceutically acceptable salt thereof,     in the manufacture of a medicament for the treatment of a disease     mediated by the NMDA receptor to a subject in need thereof, said     medicament being an extended release (ER) composition, and said     treatment comprising orally administering said composition less than     three hours before bedtime (i.e. the time at which the subject     wishes to go to sleep for the night). -   3. An extended release (ER) composition comprising amantadine, or a     pharmaceutically acceptable salt thereof, for use in a method of     reducing sleep disturbance in a human subject undergoing treatment     with amantadine, said method comprising administering said     composition less than three hours before bedtime (i.e. the time at     which the subject wishes to go to sleep for the night). -   4. Use of amantadine, or a pharmaceutically acceptable salt thereof,     in the manufacture of a medicament for reducing sleep disturbance in     a human subject undergoing treatment with amantadine, said     medicament being an extended release (ER) composition and being     adapted for administration less than three hours before bedtime     (i.e. the time at which the subject wishes to go to sleep for the     night). -   5. The use or composition of any one of embodiments 1-4 wherein     administration occurs less than 1 hour before bedtime. -   6. The use or composition of any one of embodiments 1-5, wherein the     patient has been diagnosed with Parkinson's disease. -   7. The use or composition of any one of embodiments 1-6, wherein the     composition is administered once daily. -   8. The use or composition of any one of embodiments 1-7, wherein the     composition is added to food prior to administration. -   9. The use or composition of any one of embodiments 1-8, wherein     there is no increase in plasma concentration of amantadine for at     least one hour after the administration at steady state. -   10. The use or composition of any one of embodiments 1-9, wherein     there is no increase in plasma concentration of amantadine for at     least two hours after the administration at steady state. -   11. The use of composition of any one of embodiments 1-10, wherein,     the amantadine has a single dose Tmax of 9 to 15 hours and/or a     steady state Tmax of 7 to 13 hours after administration. -   12. The use or composition of any one of embodiments 1-11, wherein     the amantadine has a single dose Tmax of 10 to 14 hours after     administration, and/or a steady state Tmax of 8 to 12 hours after     administration. -   13. The use of composition of any one of embodiments 1-10, wherein,     the amantadine has a single dose Tmax of 9 to 15 hours, and/or a     steady state Tmax of 7 to 13 hours after administration. -   14. The use or composition of any one of embodiments 1-11, wherein     the amantadine has a single dose Tmax of 10 to 14 hours after     administration, and/or a steady state Tmax of 8 to 12 hours after     administration. -   15. The use of composition of any one of embodiments 1-10, wherein,     the amantadine has a single dose Tmax of 9 to 15 hours, and/or a     steady state Tmax of 7 to 13 hours after administration. -   16. The use or composition of any one of embodiments 1-11, wherein     the amantadine has a single dose Tmax of 10 to 14 hours after     administration, and/or a steady state Tmax of 8 to 12 hours after     administration. -   17. The use or composition of any one of embodiments 1-12, wherein     the amantadine has a single dose Tmax of 11 to 13 hours after     administration, and or a steady state Tmax of 9 to 11 hours after     administration. -   18. The use or composition of any one of embodiments 1-13, wherein a     once daily oral administration of the composition to a human subject     provides a steady state plasma concentration profile characterized     by a concentration increase of amantadine of less than 25% at three     hours after the administration. -   19. The use or composition of any one of embodiments 1-14 having a     Cmax/Cmin ratio of 1.5 to 2.0. -   20. The use or composition of any one of embodiments 1-15 having a     Cmax/Cmin ratio of 1.7 to 1.9. -   21. The use or composition of any one of embodiments 1-16, wherein     the amantadine is amantadine hydrochloride or amantadine sulfate. -   22. The use or composition of any one of embodiments 1-17 wherein     the composition comprises 50 to 600 mg of amantadine, or a     pharmaceutically acceptable salt thereof. -   23. The use or composition of embodiment 18, wherein the composition     is administered as one, two, or three or four unit dosage forms each     comprising 100 to 175 mg amantadine, or a pharmaceutically     acceptable salt thereof. -   24. The use or composition of any one of embodiments 1-19 wherein     the composition comprises 200 to 420 mg of amantadine, or a     pharmaceutically acceptable salt thereof. -   25. The use or composition of embodiment 20, wherein the composition     is administered as two unit dosage forms each comprising 110 to 175     mg amantadine, or a pharmaceutically acceptable salt thereof. -   26. The use or composition of any one of embodiments 1 to 17,     wherein the composition comprises 50 to 200 mg amantadine or a     pharmaceutically acceptable salt thereof. -   27. The use or composition of embodiment 22, wherein the composition     comprises 100 to 125 mg amantadine, or a pharmaceutically acceptable     salt thereof. -   28. The use or composition of embodiment 23, wherein the composition     comprises 110 mg amantadine hydrochloride. -   29. The use or composition of any one of embodiments 1-24, wherein     oral administration of a single dose of the composition to a human     subject in a fasted state provides a maximum plasma concentration     (Cmax) of amantadine of 1.6 to 2.4 ng/ml per mg of amantadine and an     AUC_(0-inf) of 40 to 75 ng*h/mL per mg of amantadine. -   30. The use or composition of any one of embodiments 1-25, wherein     once daily oral administration of a dose of the composition to a     human subject provides a steady state plasma amantadine     concentration profile characterized by:     -   (i) a Cmax of 2.4 to 4.2 ng/ml per mg of amantadine,     -   (ii) a Cmin of 1.1 to 2.6 ng/ml per mg of amantadine, and     -   (iii) an AUC₀₋₂₄ of 44 to 83 ng*h/mL per mg of amantadine. -   31. The use or composition of embodiment 26, wherein the steady     state plasma concentration profile is further characterized by:     -   (iv) no increase in plasma concentration of amantadine for at         least one hour after the administration; and     -   (v) a Cmax/Cmin ratio of 1.5 to 2.0. -   32. The use or composition of embodiment 27, wherein the steady     state plasma concentration profile is further characterized by:     -   (iv) no increase in concentration of amantadine for at least two         hours after the administration; and     -   (v) a Cmax/Cmin ratio of 1.7 to 1.9. -   33. The use or composition of any one of embodiments 1-28, wherein     the composition has an in vitro dissolution profile of amantadine of     not more than 25% at 2 hours, 55-85% at 6 hours, and at least 80% at     12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml     water at 37° C. as the dissolution medium. -   34. The use or composition of embodiment 29, wherein the in vitro     dissolution profile of amantadine is further characterized by     release of amantadine of not more than 10% at 1 hour, 30-50% at 4     hours, and at least 90% at 12 hours -   35. The use or composition of any one of embodiments 1-30, wherein     the composition has an AUC profile after administration of a single     dose of the composition characterized by: a fractional AUC from 0 to     4 hours that is less than 5% of AUC_(0-inf); a fractional AUC from 0     to 8 hours that is about 5 to 15% of AUC_(0-inf); a fractional AUC     from 0 to 12 hours that is about 10 to 40% of AUC_(0-inf); a     fractional AUC from 0 to 18 hours that is about 25 to 60% of     AUC_(0-inf); and a fractional AUC from 0 to 24 hours that is about     40 to 75% of AUC_(0-inf) -   36. The use or composition of any one of embodiments 1-31, wherein     the composition has an AUC profile after once daily dosing of the     composition at steady state conditions characterized by: a     fractional AUC from 0 to 4 hours that is about 2 to 25% of AUC₂₄; a     fractional AUC from 0 to 8 hours that is about 15 to 50% of AUC₂₄; a     fractional AUC from 0 to 12 hours that is about 30 to 70% of AUC₂₄:     and a fractional AUC from 0 to 18 hours that is about 60 to 95% of     AUC₂₄. -   37. A pharmaceutical composition as embodied in any one of     embodiments 1, 3, or 5 to 32, or the use of any one of embodiments     2, 4 or 5 to 32, wherein said composition is for oral administration     and comprises a capsule for oral administration, said capsule     comprising a plurality of pellets, each pellet comprising:     -   (a) a pellet core comprising amantadine, or a pharmaceutically         acceptable salt thereof, and     -   (b) an extended release coating surrounding the pellet core. -   38. The use or composition of embodiment 32, wherein the extended     release coating comprises ethyl cellulose, at least one of povidone     and hydroxypropyl methyl cellulose, and a plasticizer. -   39. The use or composition of any one of embodiments 33 or 34,     wherein the pellet core comprises amantadine, or a pharmaceutically     acceptable salt thereof, and a binder coated onto a core seed. -   40. The use or composition of embodiment 35, wherein, based on the     combined weight of the pellet core and extended release coating, the     amantadine is present in amounts from 40 to 60 wt %, the binder is     present in amounts from 8 to 25 wt %, the core seed is present in     amounts from 8 to 25 wt %, the ethyl cellulose is present in amounts     from 10 to 20 wt %, the povidone is present in amounts from 1 to 4     wt %, and the plasticizer is present in amounts from 1 to 4 wt %. -   41. The use or composition of any one of embodiments 33 to 36,     further comprising a seal coating between the pellet core and the     extended release coating. -   42. The use or composition of any one of embodiments 35 to 37,     wherein the wherein the pellet core comprises a binder, selected     from the group consisting of hydroxypropyl methyl cellulose,     copovidone, and mixtures thereof. -   43. The use or composition of any one of embodiments 18 to 38,     wherein the plasticizer is selected from the group consisting of     medium chain triglycerides, diethyl phthalate, citrate esters,     polyethylene glycol, glycerol, acetylated glycerides and castor oil. -   44. A composition of any one of embodiments 33 to 39, for use in a     method of treating Parkinson's disease in a human subject in need     thereof, said method comprising orally administering said     composition.

Some embodiments herein provide a method of administering amantadine to a subject in need thereof, said method comprising orally administering an extended release (ER) composition comprising amantadine, or a pharmaceutically acceptable salt thereof, less than three hours before bedtime. In some embodiments, administration occurs less than 1 hour before bedtime. In some embodiments, the patient has been diagnosed with Parkinson's disease. In some embodiments, the composition is administered once daily. In some embodiments, the composition is added to food prior to administration. In some embodiments, there is no increase in plasma concentration of amantadine for at least one hour after the administration. In some embodiments, there is no increase in plasma concentration of amantadine for at least two hours after the administration. In some embodiments, the amantadine has a single dose Tmax of 9 to 15 hours, and/or a steady state Tmax of 7 to 13 hours. In some embodiments, the amantadine has a single dose Tmax of 10 to 14 hours after administration, and/or a steady state Tmax of 8 to 12 hours. In some embodiments, the amantadine has a single dose Tmax of 11 to 13 hours after administration, and/or a steady state Tmax of 9 to 11 hours. In some embodiments, a once daily oral administration of the composition to a human subject provides a steady state plasma concentration profile characterized by a concentration increase of amantadine of less than 25% at three hours after the administration. In some embodiments, the PK curve has a Cmax/Cmin ratio of 1.5 to 2.0. In some embodiments, the PK curve has a Cmax/Cmin ratio of 1.7 to 1.9. In some embodiments, the ratio of C-ave-day/C-ave night at steady state is 1.2 to 1.6. In some embodiments, the ratio of C-ave-morning/C-ave night at steady state is 1.3 to 1.5. In some embodiments, the average amantadine plasma concentration during the day (C-ave-day) at steady state is 500-2000 ng/ml. In some embodiments, the average amantadine plasma concentration in the morning (C-ave-morning) at steady state is 500-2000 ng/ml. In some embodiments, the amantadine is amantadine hydrochloride or amantadine sulfate. In some embodiments, the composition comprises 50 to 600 mg of amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as one, two, or three or four unit dosage forms each comprising 100 to 175 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as one or two unit dosage forms each comprising 130 to 210 mg of extended release amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is within a capsule of capsule size #1. In some embodiments, the composition comprises 200 to 350 mg of amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as two unit dosage forms each comprising 100 to 175 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 50 to 200 mg amantadine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 100 to 125 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 110 mg amantadine hydrochloride. In some embodiments, oral administration of a single dose of the composition to a human subject in a fasted state provides a maximum plasma concentration (Cmax) of 1.6 to 2.4 ng/ml per mg of amantadine, and an AUC_(0-inf) of 40 to 75 ng*h/mL per mg of amantadine. In some embodiments, once daily oral administration of a dose of the composition to a human subject provides a steady state plasma concentration profile characterized by: (a) a Cmax of 2.4 to 4.2 ng/ml per mg of amantadine; (b) a Cmin of 1.1 to 2.6 ng/ml per mg of amantadine, and (c) an AUC₀₋₂₄ of 44 to 83 ng*h/mL per mg of amantadine. In some embodiments, the steady state plasma concentration profile is further characterized by: (d) no increase in plasma concentration of amantadine for at least one hour after the administration; and (e) a Cmax/Cmin ratio of 1.5 to 2.0. In some embodiments, the steady state plasma concentration profile is further characterized by: (f) no increase in concentration of amantadine for at least two hours after the administration; and (g) a Cmax/Cmin ratio of 1.7 to 1.9. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 55-85% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 25-55% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 20% at 1 hour, 25-45% at 2 hours, 50-80% at 4 hours, and at least 80% at 8 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the in vitro dissolution profile of amantadine is further characterized by release of amantadine of not more than 10% at 1 hour, 30-50% at 4 hours, and at least 90% at 12 hours. In some embodiments, the composition has an AUC profile after administration of a single dose of the composition characterized by: a fractional AUC from 0 to 4 hours that is less than 5% of AUC_(0-inf); a fractional AUC from 0 to 8 hours that is about 5 to 15% of AUC_(0-inf); a fractional AUC from 0 to 12 hours that is about 10 to 40% of AUC_(0-inf); a fractional AUC from 0 to 18 hours that is about 25 to 60% of AUC_(0-inf); and a fractional AUC from 0 to 24 hours that is about 40 to 75% of AUC_(0-inf). In some embodiments, the composition has an AUC profile after once daily dosing of the composition at steady state conditions characterized by: a fractional AUC from 0 to 4 hours that is about 2 to 25% of AUC₂₄; a fractional AUC from 0 to 8 hours that is about 15 to 50% of AUC₂₄; a fractional AUC from 0 to 12 hours that is about 30 to 70% of AUC₂₄: and a fractional AUC from 0 to 18 hours that is about 60 to 95% of AUC₂₄.

Some embodiments herein provide a method of reducing sleep disturbance in a human subject undergoing treatment with amantadine, said method comprising administering an extended release (ER) composition comprising amantadine, or a pharmaceutically acceptable salt thereof, less than three hours before bedtime. In some embodiments, administration occurs less than 1 hour before bedtime. In some embodiments, the patient has been diagnosed with Parkinson's disease. In some embodiments, the composition is administered once daily. In some embodiments, the composition is added to food prior to administration. In some embodiments, there is no increase in plasma concentration of amantadine for at least one hour after the administration. In some embodiments, there is no increase in plasma concentration of amantadine for at least two hours after the administration. In some embodiments, the amantadine has a single dose Tmax of 9 to 15 hours, and/or a steady state Tmax of 7 to 13 hours. In some embodiments, the amantadine has a single dose Tmax of 10 to 14 hours after administration, and/or a steady state Tmax of 8 to 12 hours. In some embodiments, the amantadine has a single dose Tmax of 11 to 13 hours after administration, and/or a steady state Tmax of 9 to 11 hours. In some embodiments, a once daily oral administration of the composition to a human subject provides a steady state plasma concentration profile characterized by a concentration increase of amantadine of less than 25% at three hours after the administration. In some embodiments, the PK curve has a Cmax/Cmin ratio of 1.5 to 2.0. In some embodiments, the PK curve has a Cmax/Cmin ratio of 1.7 to 1.9. In some embodiments, the ratio of C-ave-day/C-ave night at steady state is 1.2 to 1.6. In some embodiments, the ratio of C-ave-morning/C-ave night at steady state is 1.3 to 1.5. In some embodiments, the average amantadine plasma concentration during the day (C-ave-day) at steady state is 500-2000 ng/ml. In some embodiments, the average amantadine plasma concentration in the morning (C-ave-morning) at steady state is 500-2000 ng/ml. In some embodiments, the amantadine is amantadine hydrochloride or amantadine sulfate. In some embodiments, the composition comprises 50 to 600 mg of amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as one, two, or three or four unit dosage forms each comprising 100 to 175 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as one or two unit dosage forms each comprising 130 to 210 mg of extended release amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is within a capsule of capsule size #1. In some embodiments, the composition comprises 200 to 350 mg of amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as two unit dosage forms each comprising 100 to 175 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 50 to 200 mg amantadine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 100 to 125 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 110 mg amantadine hydrochloride. In some embodiments, oral administration of a single dose of the composition to a human subject in a fasted state provides a maximum plasma concentration (Cmax) of 1.6 to 2.4 ng/ml per mg of amantadine, and an AUC_(0-inf) of 40 to 75 ng*h/mL per mg of amantadine. In some embodiments, once daily oral administration of a dose of the composition to a human subject provides a steady state plasma concentration profile characterized by: (a) a Cmax of 2.4 to 4.2 ng/ml per mg of amantadine; (b) a Cmin of 1.1 to 2.6 ng/ml per mg of amantadine, and (c) an AUC₀₋₂₄ of 44 to 83 ng*h/mL per mg of amantadine. In some embodiments, the steady state plasma concentration profile is further characterized by: (d) no increase in plasma concentration of amantadine for at least one hour after the administration; and (e) a Cmax/Cmin ratio of 1.5 to 2.0. In some embodiments, the steady state plasma concentration profile is further characterized by: (f) no increase in concentration of amantadine for at least two hours after the administration; and (g) a Cmax/Cmin ratio of 1.7 to 1.9. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 55-85% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 25-55% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 20% at 1 hour, 25-45% at 2 hours, 50-80% at 4 hours, and at least 80% at 8 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the in vitro dissolution profile of amantadine is further characterized by release of amantadine of not more than 10% at 1 hour, 30-50% at 4 hours, and at least 90% at 12 hours. In some embodiments, the composition has an AUC profile after administration of a single dose of the composition characterized by: a fractional AUC from 0 to 4 hours that is less than 5% of AUC_(0-inf); a fractional AUC from 0 to 8 hours that is about 5 to 15% of AUC_(0-inf); a fractional AUC from 0 to 12 hours that is about 10 to 40% of AUC_(0-inf); a fractional AUC from 0 to 18 hours that is about 25 to 60% of AUC_(0-inf); and a fractional AUC from 0 to 24 hours that is about 40 to 75% of AUC_(0-inf). In some embodiments, the composition has an AUC profile after once daily dosing of the composition at steady state conditions characterized by: a fractional AUC from 0 to 4 hours that is about 2 to 25% of AUC₂₄; a fractional AUC from 0 to 8 hours that is about 15 to 50% of AUC₂₄; a fractional AUC from 0 to 12 hours that is about 30 to 70% of AUC₂₄: and a fractional AUC from 0 to 18 hours that is about 60 to 95% of AUC₂₄.

Some embodiments herein provide a method of treating levodopa induced dyskinesia in a patient with Parkinson's disease, said method comprising orally administering once daily an extended release (ER) composition comprising amantadine, or a pharmaceutically acceptable salt thereof, less than about three hours before bedtime. In some embodiments, administration occurs less than 1 hour before bedtime. In some embodiments, the patient has been diagnosed with Parkinson's disease. In some embodiments, the composition is administered once daily. In some embodiments, the composition is added to food prior to administration. In some embodiments, there is no increase in plasma concentration of amantadine for at least one hour after the administration. In some embodiments, there is no increase in plasma concentration of amantadine for at least two hours after the administration. In some embodiments, the amantadine has a single dose Tmax of 9 to 15 hours, and/or a steady state Tmax of 7 to 13 hours. In some embodiments, the amantadine has a single dose Tmax of 10 to 14 hours after administration, and/or a steady state Tmax of 8 to 12 hours. In some embodiments, the amantadine has a single dose Tmax of 11 to 13 hours after administration, and/or a steady state Tmax of 9 to 11 hours. In some embodiments, a once daily oral administration of the composition to a human subject provides a steady state plasma concentration profile characterized by a concentration increase of amantadine of less than 25% at three hours after the administration. In some embodiments, the PK curve has a Cmax/Cmin ratio of 1.5 to 2.0. In some embodiments, the PK curve has a Cmax/Cmin ratio of 1.7 to 1.9. In some embodiments, the ratio of C-ave-day/C-ave night at steady state is 1.2 to 1.6. In some embodiments, the ratio of C-ave-morning/C-ave night at steady state is 1.3 to 1.5. In some embodiments, the average amantadine plasma concentration during the day (C-ave-day) at steady state is 500-2000 ng/ml. In some embodiments, the average amantadine plasma concentration in the morning (C-ave-morning) at steady state is 500-2000 ng/ml. In some embodiments, the amantadine is amantadine hydrochloride or amantadine sulfate. In some embodiments, the composition comprises 50 to 600 mg of amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as one, two, or three or four unit dosage forms each comprising 100 to 175 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as one or two unit dosage forms each comprising 130 to 210 mg of extended release amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is within a capsule of capsule size #1. In some embodiments, the composition comprises 200 to 350 mg of amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition is administered as two unit dosage forms each comprising 100 to 175 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 50 to 200 mg amantadine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 100 to 125 mg amantadine, or a pharmaceutically acceptable salt thereof. In some embodiments, the composition comprises 110 mg amantadine hydrochloride. In some embodiments, oral administration of a single dose of the composition to a human subject in a fasted state provides a maximum plasma concentration (Cmax) of 1.6 to 2.4 ng/ml per mg of amantadine, and an AUC_(0-inf) of 40 to 75 ng*h/mL per mg of amantadine. In some embodiments, once daily oral administration of a dose of the composition to a human subject provides a steady state plasma concentration profile characterized by: (a) a Cmax of 2.4 to 4.2 ng/ml per mg of amantadine; (b) a Cmin of 1.1 to 2.6 ng/ml per mg of amantadine, and (c) an AUC₀₋₂₄ of 44 to 83 ng*h/mL per mg of amantadine. In some embodiments, the steady state plasma concentration profile is further characterized by: (d) no increase in plasma concentration of amantadine for at least one hour after the administration; and (e) a Cmax/Cmin ratio of 1.5 to 2.0. In some embodiments, the steady state plasma concentration profile is further characterized by: (f) no increase in concentration of amantadine for at least two hours after the administration; and (g) a Cmax/Cmin ratio of 1.7 to 1.9. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 55-85% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 25-55% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 20% at 1 hour, 25-45% at 2 hours, 50-80% at 4 hours, and at least 80% at 8 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the in vitro dissolution profile of amantadine is further characterized by release of amantadine of not more than 10% at 1 hour, 30-50% at 4 hours, and at least 90% at 12 hours. In some embodiments, the composition has an AUC profile after administration of a single dose of the composition characterized by: a fractional AUC from 0 to 4 hours that is less than 5% of AUC_(0-inf); a fractional AUC from 0 to 8 hours that is about 5 to 15% of AUC_(0-inf); a fractional AUC from 0 to 12 hours that is about 10 to 40% of AUC_(0-inf); a fractional AUC from 0 to 18 hours that is about 25 to 60% of AUC_(0-inf); and a fractional AUC from 0 to 24 hours that is about 40 to 75% of AUC_(0-inf). In some embodiments, the composition has an AUC profile after once daily dosing of the composition at steady state conditions characterized by: a fractional AUC from 0 to 4 hours that is about 2 to 25% of AUC₂₄; a fractional AUC from 0 to 8 hours that is about 15 to 50% of AUC₂₄; a fractional AUC from 0 to 12 hours that is about 30 to 70% of AUC₂₄: and a fractional AUC from 0 to 18 hours that is about 60 to 95% of AUC₂₄.

Some embodiments herein provide a pharmaceutical composition for any of the methods described herein, wherein said composition is for oral administration and comprises a capsule for oral administration, said capsule comprising a plurality of pellets, each pellet comprising: (a) a pellet core comprising amantadine, or a pharmaceutically acceptable salt thereof, and (b) an extended release coating surrounding the pellet core. In some embodiments, the extended release coating comprises ethyl cellulose, at least one of povidone and hydroxypropyl methyl cellulose, and a plasticizer. In some embodiments, the pellet core comprises amantadine, or a pharmaceutically acceptable salt thereof, and a binder coated onto a core seed. In some embodiments, based on the combined weight of the pellet core and extended release coating, the amantadine is present in amounts from 40 to 60 wt %, the binder is present in amounts from 8 to 25 wt %, the core seed is present in amounts from 1 to 25 wt %, the ethyl cellulose is present in amounts from 10 to 20 wt %, the povidone is present in amounts from 1 to 4 wt %, and the plasticizer is present in amounts from 1 to 4 wt %. In some embodiments, the composition further comprises a seal coating between the pellet core and the extended release coating. In some embodiments, the pellet core comprises a binder selected from the group consisting of hydroxypropyl methyl cellulose, copovidone, and mixtures thereof. In some embodiments, the plasticizer is selected from the group consisting of medium chain triglycerides, diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides and castor oil.

Some embodiments herein provide a method of administering amantadine, or a pharmaceutically acceptable salt thereof, to a human subject in need thereof, said method comprising orally administering a pharmaceutical composition comprising amantadine in a capsule for oral administration, said capsule comprising a plurality of pellets, each pellet comprising: (a) a pellet core comprising amantadine, or a pharmaceutically acceptable salt thereof, and (b) an extended release coating surrounding the pellet core. In some embodiments, the extended release coating comprises ethyl cellulose, at least one of povidone and hydroxypropyl methyl cellulose, and a plasticizer. In some embodiments, the pellet core comprises amantadine, or a pharmaceutically acceptable salt thereof, and a binder coated onto a core seed. In some embodiments, based on the combined weight of the pellet core and extended release coating, the amantadine is present in amounts from 40 to 60 wt %, the binder is present in amounts from 8 to 25 wt %, the core seed is present in amounts from 1 to 25 wt %, the ethyl cellulose is present in amounts from 10 to 20 wt %, the povidone is present in amounts from 1 to 4 wt %, and the plasticizer is present in amounts from 1 to 4 wt %. In some embodiments, the composition further comprises a seal coating between the pellet core and the extended release coating. In some embodiments, the pellet core comprises a binder selected from the group consisting of hydroxypropyl methyl cellulose, copovidone, and mixtures thereof. In some embodiments, the plasticizer is selected from the group consisting of medium chain triglycerides, diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides and castor oil. Some embodiments comprise treating Parkinson's disease in a human subject in need thereof.

Some embodiments herein provide a pharmaceutical composition suitable for once daily oral administration to a patient in need thereof said composition comprising a therapeutically effective amount of amantadine or a pharmaceutically acceptable salt thereof in an extended release form which can be administered as not more than two size 0 or smaller capsules in a single daily administration. In some embodiments, the composition comprises 110-220 mg of amantadine or pharmaceutically acceptable salt thereof. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 40-80% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition comprises a plurality of pellets, each pellet comprising: (a) a pellet core comprising amantadine, or a pharmaceutically acceptable salt thereof, and (b) an extended release coating surrounding the pellet core. In some embodiments, the extended release coating comprises ethyl cellulose, at least one of povidone and hydroxypropyl methyl cellulose, and a plasticizer. In some embodiments, the pellet core comprises amantadine, or a pharmaceutically acceptable salt thereof, and a binder coated onto a core seed. In some embodiments, the composition comprises amantadine and, based on the combined weight of the pellet core and extended release coating, the amantadine is present in amounts from 40 to 70 wt %. In some embodiments, the pellet core comprises a core seed comprising sugar or microcrystalline cellulose that is between 100 and 500 microns in diameter. In some embodiments, the bulk density is between 0.5 and 1 gm/cm³. In some embodiments, the composition comprises a seal coating between the pellet core and the extended release coating. In some embodiments, the pellet core comprises a binder selected from the group consisting of hydroxypropyl methyl cellulose, copovidone, and mixtures thereof. In some embodiments, the plasticizer is selected from the group consisting of medium chain triglycerides, diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides and castor oil.

Some embodiments herein provide a method of treating Parkinson's disease in a human subject, said method comprising orally administering a composition comprising a therapeutically effective amount of amantadine or a pharmaceutically acceptable salt thereof in an extended release form which can be administered as not more than two size 0 or smaller capsules in a single daily administration. In some embodiments, the composition comprises 110-220 mg of amantadine or pharmaceutically acceptable salt thereof. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 40-80% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition comprises a plurality of pellets, each pellet comprising: (a) a pellet core comprising amantadine, or a pharmaceutically acceptable salt thereof, and (b) an extended release coating surrounding the pellet core. In some embodiments, the extended release coating comprises ethyl cellulose, at least one of povidone and hydroxypropyl methyl cellulose, and a plasticizer. In some embodiments, the pellet core comprises amantadine, or a pharmaceutically acceptable salt thereof, and a binder coated onto a core seed. In some embodiments, the composition comprises amantadine and, based on the combined weight of the pellet core and extended release coating, the amantadine is present in amounts from 40 to 70 wt %. In some embodiments, the pellet core comprises a core seed comprising sugar or microcrystalline cellulose that is between 100 and 500 microns in diameter. In some embodiments, the bulk density is between 0.5 and 1 gm/cm³. In some embodiments, the composition comprises a seal coating between the pellet core and the extended release coating. In some embodiments, the pellet core comprises a binder selected from the group consisting of hydroxypropyl methyl cellulose, copovidone, and mixtures thereof. In some embodiments, the plasticizer is selected from the group consisting of medium chain triglycerides, diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides and castor oil.

Some embodiments herein provide a method of treating levodopa induced dyskinesia in a human subject, said method comprising orally administering a composition comprising a therapeutically effective amount of amantadine or a pharmaceutically acceptable salt thereof in an extended release form which can be administered as not more than two size 0 or smaller capsules in a single daily administration. Some embodiments herein provide a method of treating traumatic brain injury in a human subject, said method comprising orally administering a composition comprising a therapeutically effective amount of amantadine or a pharmaceutically acceptable salt thereof in an extended release form which can be administered as not more than two size 0 or smaller capsules in a single daily administration. Some embodiments provide a method of treating traumatic brain injury in a human subject, said method comprising orally administering a composition comprising a therapeutically effective amount of amantadine or a pharmaceutically acceptable salt thereof in an extended release form which can be administered as not more than two size 0 or smaller capsules in a single daily administration. Some embodiments provide a method of treating fatigue in a human subject, said method comprising orally administering a composition comprising a therapeutically effective amount of amantadine or a pharmaceutically acceptable salt thereof in an extended release form which can be administered as not more than two size 0 or smaller capsules in a single daily administration. In some embodiments, the composition comprises 110-220 mg of amantadine or pharmaceutically acceptable salt thereof. In some embodiments, the composition has an in vitro dissolution profile of amantadine of not more than 25% at 2 hours, 40-80% at 6 hours, and at least 80% at 12 hours, using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. In some embodiments, the composition comprises a plurality of pellets, each pellet comprising: (a) a pellet core comprising amantadine, or a pharmaceutically acceptable salt thereof, and (b) an extended release coating surrounding the pellet core. In some embodiments, the extended release coating comprises ethyl cellulose, at least one of povidone and hydroxypropyl methyl cellulose, and a plasticizer. In some embodiments, the pellet core comprises amantadine, or a pharmaceutically acceptable salt thereof, and a binder coated onto a core seed. In some embodiments, the composition comprises amantadine and, based on the combined weight of the pellet core and extended release coating, the amantadine is present in amounts from 40 to 70 wt %. In some embodiments, the pellet core comprises a core seed comprising sugar or microcrystalline cellulose that is between 100 and 500 microns in diameter. In some embodiments, the bulk density is between 0.5 and 1 gm/cm³. In some embodiments, the composition comprises a seal coating between the pellet core and the extended release coating. In some embodiments, the pellet core comprises a binder selected from the group consisting of hydroxypropyl methyl cellulose, copovidone, and mixtures thereof. In some embodiments, the plasticizer is selected from the group consisting of medium chain triglycerides, diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides and castor oil. In some embodiments, the method comprises administering the composition to a patient less than three hours before bed time.

The present invention may be better understood by reference to the following examples, which are not intended to limit the scope of the claims.

EXAMPLE 1 Amantadine Extended Release Coated Pellet Formulations

Amantadine HCl extended release coated pellet compositions designed for nighttime administration were prepared using the components and relative amounts shown in Table 1 below. For each composition, the drug coating solution was prepared by adding HPMC 5 cps and Copovidone to isopropyl alcohol with continuous stirring. Purified water was added to this dispersion and stirring continued until a clear solution is formed. Drug (Amantadine HCl) was then added to this binder solution and stirring continued until the drug was completely dissolved. Finally, talc was added and dispersed uniformly by stirring.

Celphere beads (screen sizes #35 to #50 i.e. 300 to 500 micron) were loaded in a Wurster coating unit. The drug coating dispersion was sprayed onto the beads followed by a period of drying. The resulting drug coated pellets were sieved to retain the fraction between screens #18 and #24 (approximately 700 μm to 1 mm diameter).

The seal coating solution was prepared by adding HPMC 5 cps to isopropyl alcohol with continuous stirring. Purified water was added to this dispersion and stirring continued until a clear solution was formed. Talc was added and dispersed uniformly by stirring. The sieved drug coated pellets were loaded in a Wurster coating unit. The seal coating dispersion was sprayed over the drug coated pellets followed by a period of drying to remove the residual solvent and water in the pellets. The resulting seal coated pellets were sieved to retain the fraction between screens #18 and #24.

The ER coating solution was prepared by dissolving ethyl cellulose (viscosity 7 cps) in isopropyl alcohol and purified water and stirring until a clear solution was formed. Povidone K-90 was then dissolved in this clear solution followed by addition of plasticizer Miglyol 812N with continuous stirring to form a clear solution. The sieved seal coated pellets were loaded in a Wurster coating unit. The ER coating solution was sprayed over the seal coated pellets followed by a period of drying to affect the ER coat and remove the residual solvent and water in the pellets. After drying, magnesium stearate was spread on the top bed of the coated pellets in the annulus region followed by recirculation of the pellets in the Wurster unit to blend the magnesium stearate with the coated pellets. The resulting ER coated pellets were sieved to retain the fraction between screens #18 and #24.

The desired weight of the ER coated pellets containing the unit dose were filled into empty 1 hard gelatin capsule shell (size 1 for 100-140 mg strength) using an encapsulator equipped with pellet dosing chamber.

TABLE 1 Composition of amantadine HCl ER capsules combined w/w Component Function of capsule Pellet Core Amantadine Active 40-50%  Hydrochloride USP Microcrystalline cellulose Core seeds 10-15%  spheres (Celphere ®) Hydroxypropyl methyl Binder 10-15%  cellulose 5 cps USP Copovidone Binder 1-5% Talc USP Anti-tack 1-5% Isopropyl alcohol Solvent —¹ Water Solvent —¹ Seal Coating (optional) Hydroxypropyl methyl Coating polymer 5-10%  cellulose 3 cps USP Talc USP Anti-tack 0-5% Isopropyl alcohol Solvent —¹ Water Solvent —¹ Extended Release Coating Ethyl cellulose Coating polymer 10-20%  Povidone Pore former 1-5% Medium chain Plasticizer 1-5% triglycerides Isopropyl alcohol Solvent —¹ Water Solvent —¹ Magnesium Stearate NF Lubricant 0-1% Density of pellets 0.6-0.9 gm/cm³ NF = National Formulary ¹Purified water and isopropyl alcohol are removed during processing.

The in vitro dissolution of capsules prepared above was tested using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. Capsules meeting desired dissolution specifications released not more than 25% of the drug in 2 hours, 40-80% in 6 hours, and at least 80% at 12 hours. In an exemplary dissolution profile, there was 0% drug release at 1 hour, 12% release at 2 hours, 43% release at 4 hours, 68% release at 6 hours, 83% release at 8 hours, 92% release at 10 hours, and 97% release at 12 hours. Capsules prepared in accordance with the above method exhibited good shelf-stability, and batch-to-batch reproducibility upon scale-up.

EXAMPLE 2 Amantadine Extended Release Coated Pellet Formulation with Higher Drug Loading

Amantadine HCl extended release coated pellet compositions designed for nighttime administration are prepared using the components and relative amounts shown in Table 2 below and the manufacturing process described in example 1.

The diameter of the inert cores is 200-300 microns. The diameter of the coated pellets is 600-1200 microns. The bulk density of the coated pellets is 0.7-1.2 g/cm³.

The desired weight of the ER coated pellets containing the unit dose are filled into an empty hard gelatin capsule shell (size 1 for 170 mg strength) using an encapsulator equipped with pellet dosing chamber.

TABLE 2 Composition of amantadine HCl ER capsules combined w/w Component Function of capsule Pellet Core Amantadine Hydrochloride USP Active 50-65%  Microcrystalline cellulose spheres Core seeds 1-15%  (Celphere ®) Hydroxypropyl methyl cellulose USP Binder 5-25%  Copovidone Binder 1-5% Talc USP Anti-tack 1-5% Isopropyl alcohol Solvent —¹ Water Solvent —¹ Seal Coating (optional) Hydroxypropyl methyl cellulose USP Coating polymer 0-10%  Talc USP Anti-tack 0-5% Isopropyl alcohol Solvent —¹ Water Solvent —¹ Extended Release Coating Ethyl cellulose Coating polymer 10-20%  Povidone Pore former 1-5% Medium chain triglycerides Plasticizer 1-5% Isopropyl alcohol Solvent —¹ Water Solvent —¹ Magnesium Stearate NF Lubricant 0-1% NF = National Formulary ¹Purified water and isopropyl alcohol are removed during processing.

The in vitro dissolution of capsules prepared above are tested using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium and release not more than 25% of the drug in 2 hours, 40-80% in 6 hours, and at least 80% at 12 hours.

EXAMPLE 3 Amantadine Extended Release Coated Pellet Formulations

Amantadine HCl extended release coated pellet compositions suitable for nighttime administration were prepared using the components and relative amounts shown in Table 3 below and the manufacturing process described in Example 1.

The desired weight of the ER coated pellets containing the unit dose was filled into empty #1 hard gelatin capsule shell (100 mg strength) using an encapsulator equipped with pellet dosing chamber.

TABLE 3 Composition of amantadine HCl ER capsules combined w/w of capsule Component Function A B C Pellet Core Amantadine Active 50.15%  47.94%  45.15%  Hydrochloride USP Microcrystalline Core seeds 14.33%  13.70%  12.90%  cellulose spheres (Celphere ®) Hydroxypropyl methyl Binder 13.37%  12.79%  12.04%  cellulose USP Copovidone Binder 3.34%  3.2% 3.01% Talc USP Anti-tack 2.51%  2.4% 2.26% Isopropyl alcohol Solvent —¹ —¹ —¹ Water Solvent —¹ —¹ —¹ Seal Coating (optional) Hydroxypropyl methyl Coating 7.61% 7.27% 6.85% cellulose USP polymer Talc USP Anti-tack 0.76% 0.73% 0.69% Isopropyl alcohol Solvent —¹ —¹ —¹ Water Solvent —¹ —¹ —¹ Extended Release Coating Ethyl cellulose Coating 6.23% 9.46% 13.53%  polymer Povidone Pore 0.85% 1.29% 1.84% former Medium chain Plasticizer 0.75% 1.13% 1.62% triglycerides Isopropyl alcohol Solvent —¹ —¹ —¹ Water Solvent —¹ —¹ —¹ Magnesium Stearate NF Lubricant  0.1%  0.1%  0.1% NF = National Formulary ¹Purified water and isopropyl alcohol are removed during processing.

The in vitro dissolution of capsules prepared above were tested using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium. The results are shown in FIG. 1.

EXAMPLE 4 Amantadine Extended Release Formulation Made by Extrusion Spheronization

Amantadine HCl extended release compositions designed for nighttime administration are prepared using the components and relative amounts shown in Table 4 below and the manufacturing process described below.

A blend of amantadine HCl, microcrystalline cellulose and lactose monohydrate was prepared and a wet mass is prepared in a high shear granulator using an aqueous solution of povidone. The wet mass is extruded using 1 mm sieve and extruded mass is spheronized using a spheronizer. The pellets are dried in a tray drier to yield core pellets. The core pellets are coated with extended release coating solution in a pan coater. The desired weight of the ER coated pellets containing the unit dose is filled into empty 1 hard gelatin capsule shell (170 mg strength) using an encapsulator equipped with pellet dosing chamber.

TABLE 4 Composition of amantadine HCl ER capsules combined w/w Component Function of capsule Pellet Core Amantadine Hydrochloride USP Active 59.40% Microcrystalline cellulose Diluent 18.67% Lactose monohydrate Diluent 6.15% Povidone Binder 0.64% Water Solvent —¹ Extended Release Coating Ethyl cellulose Coating polymer 12.41% Polyethylene glycol Pore former 1.24% Dibutyl sebacate Plasticizer 1.49% Ethanol Solvent —¹

The in vitro dissolution of capsules prepared above are tested using a USP Apparatus II (Paddles) at 50 rpm with 500 ml water at 37° C. as the dissolution medium and release not more than 25% of the drug in 2 hours, 40-80% in 6 hours, and at least 80% at 12 hours.

EXAMPLE 5 Pharmacokinetic Measurement of Formulations of Amantadine ER Compared to IR Amantadine

Objective: The primary objective of the study was to confirm the PK properties of extended release formulations in example 3, to determine the pharmacokinetic profiles, safety and tolerability of three prototype formulations of ER capsules of amantadine HCl described with different release properties in Example 3 relative to a 100 mg film-coated IR amantadine HCl tablet (SYMMETREL®) given as single doses to healthy adult subjects under fasting conditions.

Study design: This was a Phase 1, randomized, single dose, open-label, four-period, crossover, fasting pharmacokinetic study in which single 100 mg doses of three formulations of Amantadine ER capsules with different release properties were compared to single 100 mg doses of marketed amantadine IR tablets (SYMMETREL®). The three ER formulations differed in the amantadine release rates in vitro, as shown in FIG. 1.

Methods: Subjects were admitted to the unit for the first period of dosing within 21 days of study screening. Subjects were dosed on the day after checking into the unit and discharged at 24 hours post dose. Subjects were asked to return after discharge for follow-up visits at 56 hours and 152 hours after dosing. Each dosing period was separated by at least 7 day washout.

After an overnight fast, the formulation was administered to the subjects while in a sitting position with 240 mL of water. Blood samples were collected at 0 (pre-dose), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 24 (discharge), and 56 hours following each dose. Plasma samples were assayed for amantadine by a validated liquid chromatography/tandem mass spectroscopy (LC/MS/MS) method. Pharmacokinetic parameters were calculated using a non-compartmental analysis with WinNonlin software (version 4.1 or higher; Pharsight Corporation).

An analysis of variance (ANOVA) was performed on the natural logarithms of Cmax and AUC0-∞ determined from the data following a single dose of study drug using linear mixed effects model. The model included effects for subject, sequence, period, and regimen. The effects of sequence, period, and regimen were fixed, while the effect of subject was random. Ratio of ER to IR for both AUC (relative bioavailability for ER formulations) and Cmax was calculated. (Adverse events were monitored throughout the study. Vital signs (pulse rate, blood pressure and body temperature), clinical laboratory measures (biochemistry, hematology, and urinalysis) and ECGs were collected at various times during the study.

Results: A total of 20 subjects participated in the study. The mean age was 25.5 years old (range 20-38 years). The study consisted of 8 male (40%) and 12 female (60%) subjects with a mean body mass index (BMI) of 23.6 kg/m2±2.85. The racial makeup was 100% Caucasian. Fifteen subjects received all 4 treatments.

The PK results from this study showed that all three of the Amantadine ER formulations reduced the rate of absorption, based on the reduced values of Cmax and increased Tmax, compared to SYMMETREL® (Table 5, FIGS. 5, 6). The IR formulation had the highest mean Cmax (277±73.9 ng/mL) and shortest median Tmax (4 h) values. Formulations A, B, and C produced progressively lower Cmax and longer Tmax values. Cmax decreased from 204±61.4 to 166±34.8 to 149±34.4 ng/mL, and median Tmax increased from 7.0, to 11.0, to 14.0 h for formulations A, B, and C, respectively. Total amantadine exposure, as measured by AUC0-∞, was slightly lower in all three Amantadine ER formulations than SYMMETREL® but all three formulations had acceptable bioavailability (85-95%).

TABLE 5 Single Dose Pharmacokinetic Parameters of Three Formulations of Amantadine ER (Formulation A, B, and C), as Compared to SYMMETREL ® (Formulati_(on) IR) 100 mg 100 mg 100 mg 100 mg Formulation A Formulation B Formulation C F_(orm)ulation IR Parameter ^(a) (n = 19⁾ (n = 17) (n = 18) (n = 18) C_(max) (ng/mL) 204 _(±) 61 166 ± 35  149 ± 34  277 ± 74  T_(max) (h) [range] 7 [5-11] 11 [5-15] 14 [₉₋₁8] 4 [2-6] A_(UC0-last) (ng*h_(/mL))  5064 ± 1573 5028 ± 2328 4525 ± 1268 5488 ± 1730 AUC₀₋ (ng*h/mL)  5545 ± ₁₉04 5724 ± 2369 5652 ± 2581 5907 ± 1907 t_(1/2) (h) 13.9 ± 3.0 16.3 ± 5.2  18.3 ± 7.5  12.3 ± 3.5  ^(a) All parameters are reported as the mean ± standard deviation (SD), except t_(max) which is reported as a median value (min to max range)

TABLE 6 Ratio ER/IR for C_(max) and AUC_(0-∞) Comparison Variable ER/IR^(a) A vs. IR C_(max) (ng/mL) 66.0% AUC_(0-∞) (ng*h/mL) 85.3% B vs. IR C_(max) (ng/mL) 60.9% AUC_(0-∞) (ng*h/mL) 94.6% C vs. IR C_(max) (ng/mL) 51.2% AUC_(0-∞) (ng*h/mL) 88.5% ^(a)Point estimate of the geometric mean ratio (ER/IR).

EXAMPLE 6 Food-Effect Evaluation of Amantadine ER

Objective: The primary objective was to demonstrate that the amantadine ER formulations suitable for nighttime administration exhibit excellent bioavailability when administered with food. We determined the pharmacokinetics of a 100 mg capsule of an amantadine ER formulation (Example 3, Formulation B), when administered both with a high fat meal and in a fasted state.

Study Design: This was a Phase 1, randomized, single dose, open-label, two-period, crossover, food-effect study to compare single 100 mg doses of Formulation 1 in healthy adult (18 to 45 years of age) male and female subjects in fed and fasted states. The study consisted of a 21-day to -2 day screening phase (prior to the scheduled dosing day) and two treatment periods, Period 1 and Period 2, with an 8-day wash-out period between treatment periods.

Methods: After an overnight fast, the formulation was administered to the subjects while in a sifting position with 240 mL of water at ambient temperature for the fasted condition. For the fed condition, after the overnight fast, subjects were served a high fat and high calorie test meal (Guidance for Industry Food-Effect Bioavailability and Fed Bioequivalence Studies, December 2002) as breakfast, which they were required to consume completely within 30 minutes before taking the study medication. Subjects were randomized to one of two sequences, each composed of treatment administration under fed and fasted conditions separated by an eight day wash out period.

For each period, pharmacokinetic blood samples were collected at pre-dose and at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 24, 28, 48, 72, 96 and 144 hours after dosing in each period. Subjects were housed in the clinical facility at least 15 hours before investigational product administration and remained in the clinical facility for at least 28 hours after administration of the investigational product in each period. Samples after 28 hours in each period were collected on an ambulatory basis. Amantadine in plasma was quantified by a validated LC/MS/MS method. The pharmacokinetic parameters were calculated from the drug concentration-time profile by non-compartmental model using WinNonlin Professional Software—Version 5.0.1 (Pharsight Corporation, USA) for amantadine. Absence of food effect was defined as met if the point estimates and 90% confidence intervals (CI) for the ln-transformed C_(max), AUC_(last) and AUC_(∞) fed/fasting ratios of the population means were entirely within the standard accepted range of 80% to 125%. All statistical analyses for amantadine were performed using PROC MIXED of SAS® Release 9.1.3 (SAS Institute Inc., USA).

Routine safety monitoring was conducted during and after dosing in all subjects.

Results: A total of 26 subjects participated in the study, 19 (73%) male and 7 (27%) female. The mean age was 26 years (range 19-44) and the mean BMI was 22.4 kg/m² (range 18.1-29.8). The racial makeup was 100% Asian. All subjects received at least one dose of study drug and were included in the safety analysis. Twenty-four (92.3%) subjects completed the study and were included in the pharmacokinetic analysis. Two subjects (7.7%) were withdrawn prior to completion of the study due protocol deviations.

The results of this study (Table 7) indicate that the single dose pharmacokinetics of Formulation B are not affected by food. The rate, as measured by C_(max), and the extent, as measured by AUC_(0-last) and AUC_(0-∞), of absorption of amantadine, administered with and without food, were equivalent (Table 8).

TABLE 7 Mean ± SD Pharmacokinetic Parameters after Single Dose Administration of 100 mg of Formulation B in Fed and Fasted States Mean ± SD (Un-transformed data) n = 24 Parameters (Units)^(a) Fasted State Fed State T_(max) (h)    11.9 ± 2.1 (8-15)     9.5 ± 2.4 (5-16) C_(max) (ng/mL) 198.8 ± 34.7  219.4 ± 41.5  AUC_(0-last) (ng*h/mL) 5571.2 ± 1654.2 5394.4 ± 1581.5 AUC_(0-∞) (ng*h/mL) 5663.1 ± 1677.4 5476.6 ± 1590.7 t_(1/2) (h) 11.9 ± 2.8  11.5 ± 2.0  t_(lag) (h) 1.0 2.0 ^(a)All parameters are reported as the mean ± standard deviation (SD). t_(max) is reported as the mean ± SD (min to max range).

TABLE 8 Geometric Least Squares Mean, Ratios and 90% Confidence Interval for Formulation B (n = 24) in Fed and Fasted States ln-transformed data Geometric Least Squares Mean 90% Confidence Parameters Fed Fasted Ratio Interval (Units) State State (Fed/Fasted)% (Parametric) C_(max) 215.6 195.8 110.1 104.4-116.2%  (ng/mL) AUC_(0-last) 5195.9 5344.2 97.2 91.0-103.8% (ng*h/mL) AUC_(0-∞) 5280.3 5434.7 97.2 90.9-103.8% (ng*h/mL)

Conclusion: The results of this study indicate that the single dose pharmacokinetics of amantadine ER are not affected by food. The rate, as measured by C_(max), and the extent, as measured by AUC_(0-last) and AUC_(0-∞), of absorption of amantadine, administered with and without food, were equivalent.

EXAMPLE 7 Pharmacokinetic Study Comparing Once-Daily Administration of Amantadine HCl ER Capsules with Twice-Daily Administration of Amantadine HCl IR Tablets in Healthy Adults Under Fasting Conditions

Objective: The primary objective of this study was to measure at steady state under repeat or chronic dosing the pharmacokinetics of an ER amantadine formulation suitable for nighttime administration, and enable the calculation of critical PK parameters for future safety and efficacy studies (i.e., Cave-morning, Cave-day, Cave-night) of ER amantadine formulations administered at night. We compared the single dose and repeat dose pharmacokinetics of amantadine HCl administered twice daily as a commercially available immediate release (IR) formulation to a once daily amantadine extended release (ER) formulation (Example 3, Formulation B).

Study Design: This was a two period, multiple dose, crossover study. After a 21 day screening period, 26 healthy male and female subjects were randomized to receive one of two treatments (amantadine ER 200 mg once daily or amantadine IR 100 mg twice daily) in Period-I, then crossed over to receive the other treatment in Period-II.

Methods: Study drug administration started on day 1. Study drug was not administered on Day 2. Multiple dosing commenced on day 3 and continued for 7 days (through day 9). A washout period of 8 days separated the dose administrations. The study drug was administered with 240 mL of drinking water. No other fluids were allowed within 1 hour of dosing. For each period, pharmacokinetic blood samples were collected at pre-dose and at 1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 24, 28, 36, and 48 hours after the first dose. The morning trough (pre-dose) blood samples were collected on Days 7 and 8. Blood samples were again collected immediately before the morning dose on Day 9 and at 1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 24, 28, 48, 72, and 96 hours thereafter. Samples after 28 hours following the morning dose on day 9 were collected on an ambulatory basis in each period. Amantadine in plasma was quantified by a validated LC/MS/MS method. The pharmacokinetic parameters were calculated from the drug concentration-time profile by non-compartmental model using WinNonlin Professional Software—Version 5.0.1 (Pharsight Corporation, USA) for amantadine.

Statistical analyses were conducted to assess the pharmacokinetic profile of single dose and repeat dose amantadine HCl administered twice daily as a commercially available immediate release (IR) formulation compared to a once daily extended release (ER) formulation (Formulation B). An analysis of variance (ANOVA) was performed on the natural logarithms of C_(max), C_(min), and AUC₂₄ determined from the data following the dose of study drug on study day 9 using linear mixed effects model. The model included the fixed effects for sequence, period, regimen and a random subject effect. The confidence intervals were used to perform the 2 one-sided tests procedure for equivalence assessment. The confidence intervals were obtained by exponentiating the endpoints of the confidence intervals for the difference of mean logarithms obtained within the framework of the ANOVA model. The upper and lower limits of confidence intervals from the natural-log transformed data were back-exponentiated to obtain the 90% confidence interval for the ratio of geometric means. Equivalence was established if the exponentiated 90% confidence interval fell entirely within the interval (80.00%, 125.00%).

Repeated measures ANOVA was carried out for comparison of C_(min) for day 7, 8 and 9 at 5% level of significance on both untransformed and ln-transformed data. Steady state was demonstrated if the repeated measures ANOVA test was found to be non-significant. The statistical analysis for amantadine was performed using PROC MIXED of SAS® Release 9.1.3 (SAS Institute Inc., USA).

Routine safety monitoring was conducted during and after dosing in all subjects, and at the end of the study.

Results: A total of 26 subjects participated in the study, 22 (84.6%) male and 4 (15.4%) female. The mean age was 26 years (range 19-42) and the mean BMI was 22.9 kg/m² (range 18.1-28.8). The racial makeup was 100% Asian. All subjects received at least one dose of study drug and were included in the safety analysis. Twenty-four (92.3%) subjects completed the study and were included in the pharmacokinetic analysis. Two subjects (7.7%) were withdrawn from the PK analysis prior to completion of the study due to vomiting within 12 hours of dosing, which was a pharmacokinetic exclusion criterion.

As expected from its half-life, once daily administration of amantadine ER and twice daily dosing of amantadine IR resulted in accumulation as measured by higher C_(max) and AUC on Day 9 compared to Day 1 (Table 9 and FIG. 2). Steady state was achieved by Day 9 for both formulations as demonstrated by similar trough levels on Days 7, 8 and 9 (data not shown). At steady state (Day 9) plasma concentrations (FIG. 2, Table 9) and pharmacokinetic parameters (Table 9) were comparable for both formulations. Furthermore, the formulations are equivalent in terms of the extent and the rate of absorption of amantadine as measured by steady state C_(max), C_(min) and AUC₀₋₂₄ (Table 9), where equivalency is defined by the 90% CIs of the ratio of the least square means of the test versus reference for steady state C_(max), C_(min) and AUC₀₋₂₄ of Amantadine ER to Amantadine IR falling within 80%-125%.

TABLE 9 Mean (±SD) Pharmacokinetic Parameters of Amantadine after Single and Multiple Dose Administration of IR (100 mg BID) and ER (200 mg QD) Formulations Formulation IR (n = 24) ER (n = 24) Parameter (Units)^(a) Day 1 Day 9 Day 1 Day 9 t_(1/2) (h) 13.2 ± 2.8 12.6 ± 2.4 13.7 ± 3.6 12.8 ± 2.2  [9.1-18.8] [9.4-18.1] [9.1-22.7] [9.2-17.4] t_(max) (h) 14.42 ± 0.88 12.6 ± 4.5 11.4 ± 1.9 10.3 ± 2.0 [13-16] [1-15] [8-18] [8-18] C_(max) (ng/mL) 530 ± 80  728 ± 153 431 ± 84  665 ± 179 [407.5-752.7] [538.4-1101.8] [313.5-559.9]  [444.4-1140.0] AUC_(0-last) (ng h/mL) 11989 ± 2224 23040 ± 8273 11171 ± 2773 21362 ± 8946  [9243-17106] [13133-46446]  [7326-16970] [10821-47134]  AUC_(0-∞) (ng h/mL) 13685 ± 3324 NA 12900 ± 4087 NA [10167-20989] [7817-22153] AUC₀₋₂₄ (ng h/mL)  7695 ± 1026 13752 ± 3586  7173 ± 1367 12680 ± 3879  [5967-10171] [9085-22519] [5021-9552]  [7896-23058] C_(min) (ng/mL) —  412.4 ± 142.6 —  374.9 ± 151.7 [218.5-795.2]  [172.2-767.1]  ^(a)All parameters are reported as the mean ± SD, [min to max range] NA = not applicable

Certain additional PK parameters that are important in determining the suitability of the ER amantadine formulation for once daily, night time administration are also reported in Table 10.

TABLE 10 Additional Steady State PK parameters of Amantadine ER ER 200 mg QD IR 100 mg BID Cmax/Cmin 1.86 1.68 C-ave-8-16 hrs(ng/ml) 614 586 C-ave-8-12 hrs (ng/ml) 643 510 C-ave-16-24 hrs (ng/ml) 502 569 C-ave-0-8 hrs (ng/ml) 465 586 C-ave-8-16 hrs/C-ave-0-8 hrs 1.32 1.00 C-ave-8-12 hrs/C-ave-0-8 hrs 1.38 0.87 % Change in Plasma  5% 55% Concentration 0-3 hrs % Change in Plasma 23% 48% Concentration 0-4 hrs AUC 0-4 as % of AUC 24 12% N/A AUC 0-8 as % of AUC 24 30% N/A AUC 0-12 as % of AUC 24 51% N/A

Conclusion: the ER amantadine formulation exhibits the desired steady state PK properties that would make the same suitable for administration at night and for achieving desired efficacy and tolerability benefits. Specifically, the ER amantadine formulation administered once daily at night results in relatively slow initial rise in amantadine plasma concentration, higher average amantadine plasma concentrations 8 to 12 hours after administration relative to 0-8 hours after administration and thus if administered at night higher ratios of average day time to night time amantadine plasma concentrations relative to IR amantadine. Thus this formulation is well suited for administration at higher doses than current practice that are expected to be relatively well tolerated and potentially provide superior efficacy in the treatment of LID, fatigue and Parkinson's disease.

EXAMPLE 8 Study Comparing Administration of Amantadine HCl ER Capsules Once Nightly with Twice-Daily Administration of Amantadine HCl IR Tablets in Normal Healthy Volunteers

Objective: The primary objective is to compare the effects on sleep of amantadine extended release (ER) capsules (Formulation B) administered once daily at bedtime with amantadine immediate release (IR) tablets administered twice daily in normal healthy volunteers. This ER formulation exhibits a Cave,day/Cave, night=1.30.

Study Design: This is a single-center, double-blind, triple-dummy, randomized, cross-over study to compare the effects on sleep of amantadine ER capsules, QHS, amantadine IR tablets BID, and caffeine caplets (active comparator) in 30 normal healthy volunteers as assessed by overnight polysomnography (PSG) and standardized questionnaires (Stanford Sleepiness Scale (SSS); Modified Epworth Sleepiness Scale (m-ESS)/Karolinska Sleepiness Scale (KSS); Toronto Hospital Alertness Test (THAT)/ZOGIM Alertness Scale (ZOGIM-A); Visual analog scale of sleepiness/alertness (VAS)).

Study drugs are administered in 3 dosing periods. A single day's dosage of one drug is administered per dosing period. Each day of dosing is separated by a washout period of 1 week. A single day's dosage of amantadine ER (Formulation B) consists of one 220 mg capsule (or 2×110 mg capsule) administered at bed time (QHS; defined as 23:00 h for the purposes of this study). A single day's dosage of amantadine IR consists of one 100 mg capsule administered twice a day (BID; defined as 8:00 h and 16:00 h for the purposes of this study). A single day's dosage of caffeine consists of one 100 mg capsule administered three times a day (TID; defined as 8:00 h, 16:00 h, & 23:00 h for the purposes of this study).

All subjects are dosed three times a day, at 8:00 h, 16:00 h, & 23:00 h. At each hour of dosing, every subject receives either the active drug or the matching placebo for each of the 3 treatments. Whether the capsule, tablet, or caplet administered at a specific hour of dosing contains active study drug or is a placebo dummy is determined according to the dosing sequence and period to which the subject is assigned.

Consented subjects who meet eligibility criteria are randomized equally to one of 3 treatment sequences (groups), each comprising 3 single-day treatment periods separated by 1 week washout periods as described above. Additionally, there is a one-day, single-blind, placebo run-in prior to each double-blind dosing day. This is to allow subjects to acclimate to sleeping in the Clinical Research Unit (CRU) under conditions of PSG recording and to establish individual baseline (BL) PSG characteristics.

For each dosing period, subjects are admitted to a CRU equipped with a sleep laboratory the day before the first day of dosing with active study drug. They stay in the CRU overnight and through the entirety of the active drug-dosing day. They again stay overnight and then are discharged from the CRU the morning of the following day. For the first dosing period, the day of admission to the CRU (Day-1) constitutes the last day of the screening phase, and the day of discharge from the CRU constitutes the first day of the first washout period (Day 2). For the second dosing period, the day of re-admission to the CRU (Day 7) constitutes the last day of the first washout period, and the day of discharge (Day 9) will constitute the first day of the second washout period. For the third dosing period, the day of re-admission to the CRU (Day 14) constitutes the last day of the second washout period, and the day of discharge (Day 16) constitutes the first day of the follow-up phase.

On the day of admission (or re-admission) to the CRU, subjects undergo routine laboratory and vital sign testing. They are administered one each of the placebo dummies (for amantadine ER, amantadine IR, & caffeine) at 16:00 h and at 23:00 h in single-blind fashion. They are questioned for adverse events (AEs) and have vital signs checked immediately prior to each dosing. Blood is drawn for routine laboratory testing and toxicology screen prior to the 16:00 h dosing. Subjects spend the night in the sleep lab under conditions of PSG recording.

On the day of dosing with active study drug, subjects are awakened at 7:00 h and fill out a battery of sleep and alertness questionnaires. They receive study drug (active or placebo) at 8:00 h, 16:00, and 23:00 h. They are questioned for AEs and have vital signs checked immediately prior to each dosing. Blood is drawn to measure plasma amantadine concentrations prior to the 23:00 h dosing.

On the day after dosing with active study drug, subjects are awakened at 7:00 h and fill out a battery of sleep and alertness questionnaires. Shortly before 8:00 h, i.e., 9 hours after the last dosing time, they are questioned for AEs and have vital signs checked. Also, blood is drawn to measure plasma amantadine concentrations. Instructions for contacting the site to report any AEs are reviewed with the subjects prior to their discharge from the CRU. The schedule for returning to the PSU for the next dosing period (this applies to returning for Periods 2 & 3) or for telephone contact (this applies to the follow-up after the third dosing period) is be reviewed.

All subjects receive a follow-up telephone call 3 days following discharge from the CRU (Day 19).

AEs and concomitant medications are monitored throughout the study. Blood samples for measurement of blood plasma concentrations are drawn immediately prior to the 23:00 h dosing time on Days 1, 8, and 15, and at approximately 8:00 h on Days 2, 9, and 16.

Sleep parameters and measurements of sleepiness and alertness at each time point are listed by subject. Both composite scores and scores from the individual components of the PSG and questionnaires are tabulated and analyzed. For each parameter measured, descriptive summary statistics are calculated by sequence and treatment, including means (or medians, as appropriate), ranges, and standard deviations (SDs).

Inferential statistics are performed on selected results wherein the magnitude of the differences between the means across treatment groups relative to the variance suggests a possible differential treatment effect. Continuous variable data is analyzed by parametric statistics (repeated measures analysis of variance with appropriate supplemental post-hoc analyses and/or paired t-test). Categorical data and data not conforming to a normal distribution is analyzed by non-parametric statistics (Wilcoxon signed rank test). PSG data may also be assessed by multivariate analyses and/or spectral analyses.

Results: A lack of increase in, or reduction of, sleep disturbances with QD administration of 220 mg of amantadine ER compared to BID administration of amantadine IR, as measured by PSG and a standardized sleep questionnaire (e.g. SSS, m-ESS, KSS, THAT, ZOGIM-A, or VAS), demonstrates the suitability of amantadine ER for once daily administration at bedtime.

EXAMPLE 9 Study Comparing the Effects on Sleep and Efficacy of Amantadine HCl ER Capsules Administered Once Daily at Night Relative to Amantadine HCl IR Capsules Administered Twice Daily in Parkinson's Patients

Objective: To compare the effects on sleep and efficacy of amantadine extended release (ER) capsules.

Study Design: This is a Multi-Center, Double-Blind, Randomized Study to Compare the Effects on Sleep and Efficacy of Amantadine Extended Release (ER) Capsules in 120 Parkinsons Patients as assessed by UPDRS (Unified Parkinson's Disease Rating Scale), UPDRS-IV (Unified Parkinson's Disease Rating Scale Part IV), AIMS (Abnormal Involuntary Movement Scale), overnight polysomnography (PSG) and standardized questionnaires (Stanford Sleepiness Scale (SSS); Modified Epworth Sleepiness Scale (m-ESS)/Karolinska Sleepiness Scale (KSS); Toronto Hospital Alertness Test (THAT)/ZOGIM Alertness Scale (ZOGIM-A); Visual analog scale of sleepiness/alertness (VAS)).

All study drugs are administered orally. Treatment A consists of a placebo capsule administered in the morning and two 110 mg capsules of Amantadine (ER) and a placebo capsule administered at bed time. Treatment B consists of a placebo capsule administered in the morning and three 110 mg capsules of Amantadine (ER) administered at bed time. Treatment C consists of a 100 mg capsule of Amantadine IR administered in the morning and a 100 mg capsule of Amantadine IR and two placebo capsules administered at bed time. Treatment D consists of a placebo capsule administered in the morning and 3 placebo capsules administered at bed time.

Consented subjects who meet eligibility criteria are randomized equally to one of 3 treatment groups, each comprising 14-day treatment periods. Additionally, there is a one-day, single-blind, placebo run-in prior to each double-blind dosing day. This is to allow subjects to acclimate to sleeping in the Clinical Research Unit (CRU) under conditions of PSG recording and to establish individual baseline (BL) PSG characteristics.

For each dosing period, subjects are admitted to a CRU equipped with a sleep laboratory the day before the first day of dosing with active study drug. They stay in the CRU overnight and through the entirety of the active drug-dosing day. They again stay overnight and then are discharged from the CRU the morning of the following day.

Parkinson's scores are recorded in the mornings on days 1, 7 and 14 using standard scoring methods, including the UPDRS and AIM.

AEs and concomitant medications are monitored throughout the study.

Sleep parameters and measurements of sleepiness and alertness at each time point are listed by subject. Both composite scores and scores from the individual components of the PSG and questionnaires are tabulated and analyzed. For each parameter measured, descriptive summary statistics are calculated by sequence and treatment, including means (or medians, as appropriate), ranges, and standard deviations (SDs).

Inferential statistics are performed on selected results wherein the magnitude of the differences between the means across treatment groups relative to the variance suggests a possible differential treatment effect. Continuous variable data is analyzed by parametric statistics (repeated measures analysis of variance with appropriate supplemental post-hoc analyses and/or paired t-test). Categorical data and data not conforming to a normal distribution is analyzed by non-parametric statistics (Wilcoxon signed rank test). PSG data may also be assessed by multivariate analyses and/or spectral analyses.

Results: An improvement in UPDRS, UPDRS-IV, AIM, lack of increase in, or reduction of, sleep disturbances, as measured by PSG and a standardized sleep questionnaire (e.g. SSS, m-ESS, KSS, THAT, ZOGIM-A, or VAS), demonstrates the suitability of amantadine ER for once daily administration at bedtime.

EXAMPLE 10 Simulated Pharmacokinetic Characteristics of Higher Strength, Amantadine ER Formulations Administered at Nighttime

Objective: The objective is to use the data generated in the clinical study described in Example 7 to predict steady state plasma concentration-time profiles of various IR and ER amantadine regimens at different dose levels to show the benefits of higher strength amantadine ER formulations administered at nighttime.

Methodology: Plasma concentration-time profiles from healthy volunteers that received multiple doses of the ER and IR formulations of amantadine per study procedures described in Example 7 (ADS-5101-MD-104) were used to develop a pharmacokinetic model describing each of the two formulations. This study was an open-label, randomized, two-treatment, two-period, two-way crossover study comparing once-daily amantadine ER capsules and twice-daily amantadine IR tablets in 26 healthy, adult male and female volunteers. Complete data from 24 individuals were used in this exercise. Blood samples for pharmacokinetic evaluation were collected after single dosing on Day 1 and at steady state on Day 9. In the first step of the analysis, WinNonlin 5.2.1 (Pharsight Corp., Mountain View, Calif.) was used to fit a one-compartment model with first-order input and first-order output, weighted 1/y (where y is the amantadine plasma concentration), to each individual's plasma concentration-time data obtained after single (Day 1) and repeated (Day 9) dose administration of amantadine IR and ER; the fitting was done separately for both formulations, but simultaneously for both days. Modeling assumptions employed include dose proportionality and constant clearance as a function of time.

The model is described by the following equation:

$\begin{matrix} {C = {\frac{FD}{V\left( {k_{a} - k} \right)}\left\lbrack {{\exp \left( {- {k\left( {t - t_{{lag})}} \right)}} \right)} - {\exp \left( {- {k_{a}\left( {t - t_{{lag})}} \right)}} \right)}} \right\rbrack}} & {{Equation}\mspace{14mu} 1} \end{matrix}$

where C is the plasma concentration, F is the absolute bioavailability, D is dose, V is the volume of distribution, k_(a) is the absorption rate constant, k is the elimination rate constant, t is time, and t_(lag) is the lag time of absorption. The goodness of fit was verified by comparing the individual model predicted and observed concentration-time data from Study ADS-5101-MD-104. After Equation 1 was fitted to each individual's plasma concentration-time data, model parameter estimates of V/F, k_(a), k, and t_(lag) were obtained for each of the 24 subjects. The goodness of the prediction at steady state was confirmed by comparing the observed data and predicted steady-state concentrations of amantadine obtained after daily dosing of 200 mg as the ER and IR formulations (Day 9).

In the second step of the analysis, individual model parameter estimates were used to simulate steady-state concentration-time profiles for each individual for both formulations by reinserting the individual parameter estimates into Equation 1, and summing the contribution of 7 sequential days of dosing, according to the following dosing regimens:

-   -   1. Once Daily (QD) dosing of 260, 340, and 420 mg of the ER         formulation to steady state     -   2. Three times daily (TID) dosing of 100 mg of the IR         formulation to steady state     -   3. Twice daily (BID) dosing of 100 mg of the IR formulation to         steady state

Results: FIG. 4 shows the simulated steady state plasma concentration time profiles for various ER amantadine doses along with various regimes of IR amantadine. Table 11 summarizes values of the pharmacokinetic parameters that affect the efficacy and tolerability of ER amantadine when administered at night.

TABLE 11 PK parameters associated with nighttime administration - morning peak benefit measured for ER Amantadine formulation IR 100 IR 100 ER 260 ER 340 ER 420 mg BID mg TID mg QD mg QD mg QD Cmax (ng/ml) 669 936 834 1091 1348 Cmin (ng/ml) 435 731 461 603 745 Cmax/Cmin 1.54 1.28 1.81 1.81 1.81 C-ave-day 571 845 766 1002 1238 (6 am-4 pm) (ng/ml) C-ave-morn 479 870 824 1078 1332 (6 am-10 am) (ng/ml) C-ave-even 522 852 591 773 955 (4 pm-10 pm) (ng/ml) C-ave-night 596 843 616 805 995 (10 pm-6 am) (ng/ml) C-ave-day/C-ave-night 0.96 1.00 1.24 1.24 1.24 C-ave-morn/C-ave-night 0.80 1.03 1.34 1.34 1.34 C-ave-day relative to 1.00 1.48 1.34 1.76 2.17 100 mg BID IR

As shown in Table 11 and in the figures, the ER amantadine formulations administered once daily at night result in higher ratios of average day time to night time amantadine plasma concentrations relative to IR amantadine and are predicted to be relatively well tolerated. The ER formulations also result in average day time amantadine plasma concentrations that are 1.3 to 2.2 fold that of IR amantadine administered at 100 mg twice daily and is predicted to result in significantly enhanced efficacy when administered to patients in the clinical study described in Example 11 below.

EXAMPLE 11 A Randomized, Double-Blind, Placebo-Controlled Study of the Efficacy and Safety of Amantadine Extended Release Oral Capsules for the Treatment of Levodopa-Induced Dyskinesia in Parkinson's Disease

Study Objectives: This study is designed to confirm dose range of Amantadine Extended Release (ER) oral capsules dosed once daily at nighttime for the treatment of levodopa-induced dyskinesia (LID) in subjects with Parkinson's Disease (PD). In addition, the study is designed to demonstrate the safety and tolerability of Amantadine ER oral capsules dosed once daily for the treatment of LID in subjects with PD. Finally, to confirm the steady-state pharmacokinetics of the Amantadine ER dosing regimens in Parkinsons patients and to correlate C-ave-day, Cave-morning, C-ave-morning/C-ave-night and C-ave-day/C-ave-night with the efficacy and tolerability of amantadine.

Study design: This will be a multi-center, randomized, double-blind, placebo-controlled, 4-arm parallel group study of Amantadine ER in subjects with PD and LID/Consenting subjects who meet eligibility criteria will be randomized 1:1:1:1 to receive one of the following 4 treatments, each administered as once daily, dosed at night, for 8 weeks:

-   -   Treatment A: Placebo,     -   Treatment B: 260 mg Amantadine ER (ADS-5102),     -   Treatment C: 340 mg Amantadine ER (ADS-5102)     -   Treatment D: 420 mg Amantadine ER (ADS-5102)

Subjects who are randomized to Treatment C or D (higher dose amantadine groups) will receive, in double-blind fashion, 260 mg Amantadine ER once daily during week 1, with an increase to either 340 mg or 420 mg once daily at the beginning of week 2. Dosing will continue through week 8.

Following completion of the baseline visit and randomization, subjects will return to the clinic after 1, 2, 4, 6, and 8 weeks of dosing, with a follow-up visit 14 days following the last dose of study drug. Study visits and assessments will be scheduled during morning hours when possible (9 am through 1 pm). A set of two 24-hour diaries will be completed during 48 hours prior to randomization and 48 hours prior to selected study visits. The diary will be used to score five different conditions in 30-minute intervals: Sleep, OFF, ON without dyskinesias, ON with nontroublesome dyskinesias, ON with troublesome dyskinesias.

Blood samples will be collected at selected study visits for determination of amantadine plasma concentrations, and evaluation of steady-state population pharmacokinetics. Subject participation during the study will be up to 12 weeks and will include a 2-week (maximum) screening period, 8-week (maximum) treatment period, and a 2-week follow-up period. Subjects who are unable to tolerate their assigned study drug assignment will permanently discontinue study drug and continue to be followed for safety through 2 weeks following the last dose of study drug.

Patient Eligibility Criteria: Subjects are eligible to take part in the study if they meet the inclusion and do not meet the exclusion criteria. Selected key criteria are as follows:

Inclusion Criteria:

-   -   Male or female adults, residing in the community (i.e. not         residing in an institution)     -   Between 30 and 75 years of age, inclusive     -   Ambulatory or ambulatory-aided (e.g. walker or cane) ability,         such that the subject can come to required study visits     -   Knowledgeable and reliable caregiver/study partner, if         appropriate, to accompany the subject to study visits     -   Signed a current IRB/IEC-approved informed consent form     -   Following training, the subject is willing and able to         understand and complete the 24-hour home diary (caregiver         assistance allowed)     -   Idiopathic Parkinson's Disease, complicated by dyskinesia (a         MDS-UPDRS score will be determined during screening, but a         minimum score is not required)     -   On a stable regimen of antiparkinson's medications, including         levodopa, for at least 30 days prior to screening, and willing         to continue that regimen during study participation     -   Presence of dyskinesia, defined as a minimum UDysRS score

Exclusion Criteria:

-   -   Presence of other neurological disease that may affect         cognition, including, but not limited to Alzheimer's dementia,         Huntington's disease, Lewy body dementia, frontotemporal         dementia, corticobasal degeneration, or motor or sensory         dysfunction secondary to stroke or brain trauma.     -   Presence of cognitive impairment, as evidenced by a Mini-mental         State Examination (MMSE) score of less than 24 during screening.     -   Presence of an acute major psychiatric disorder (e.g., Major         Depressive Disorder) according to DSM-IV-TR or symptom (e.g.,         hallucinations, agitation, paranoia) that could affect the         subject's ability to complete study assessments     -   Presence of sensory impairments (e.g., hearing, vision) that         would impair the subject's ability to complete study assessments     -   History of alcohol or drug dependence or abuse, according to         DSM-IV criteria, within 2 years prior to screening     -   History of seizures (excluding febrile seizures of childhood)     -   History of stroke or TIA within 2 years prior to screening     -   History of myocardial infarction, NYHA Congestive Heart Failure         Class 3 or 4, or atrial fibrillation within 2 years prior to         screening     -   History of cancer within 5 years prior to screening, with the         following exceptions: adequately treated non-melanomatous skin         cancers, localized bladder cancer, non-metastatic prostate         cancer or in situ cervical cancer (these exceptions must be         discussed with and approved by the Medical Monitor before study         entry)     -   Any of the following lab abnormalities; Hemoglobin<10 g/dL,         WBC<3.0×10⁹/L, Neutrophils<1.5×10⁹/L, Lymphocytes<0.5×10⁹/L,         Platelets<100×10⁹/L, Hemoglobin A1C>9%, or Aspartate         aminotransferase (AST) and/or alanine aminotransferase (ALT)>2         times the upper limit of normal     -   Estimated GFR<50 mL/min/1.73 m² by Modification of Diet in Renal         Disease (MDRD) or Cockcroft-Gault equation     -   Any clinically significant ECG abnormalities     -   Inability to swallow oral capsules, or a history of         gastrointestinal malabsorption that would preclude the use of         oral medication

Study Endpoints: The primary efficacy endpoint will be the change from baseline to week 8 in the Unified Dyskinesia Rating Scale (UDysRS) score. Key secondary endpoints will include:

-   -   ON time without troublesome dyskinesia (ON without dyskinesia         plus ON with non-troublesome dyskinesia), based on a         standardized PD home diary     -   Unified Parkinson's Disease Rating Scale (MDS-UPDRS), overall         score     -   Fatigue as measured by the Fatigue Severity Scale (FSS). This         scale includes 9 questions that are completed by the patient         using a rating scale from 1 (strongly disagree) to 7 (strongly         agree). This fatigue scale is recommended by MDS for both         screening and severity rating (2010)     -   Safety, including adverse events, safety-related study drug         discontinuations, vital signs, and laboratory tests.

The following mixture of traditional and new scales have been selected for this phase 2 study:

-   -   Unified Dyskinesia Rating Scale (UDysRS) will be used for         primary outcome measure. This scale has four parts, and a total         possible score of 104:         -   I: Historical Disability (patient perceptions) of             On-Dyskinesia impact         -   II: Historical Disability (patient perceptions) of             Off-Dystonia impact         -   III: Objective Impairment (dyskinesia severity, anatomic             distribution, and type, based on 4 observed activities)         -   IV: Objective Disability based on Part III activities     -   ON time without troublesome dyskinesia, based on a standardized         Parkinson's Disease home diary (suggest Test Diary II), [33]         will be a secondary outcome measure. This scale has been used in         number of studies with mixed success [34]. However, most KOLs         feel that subject-reported dairy data must be collected, and         needs to support the primary outcome measure.     -   Unified Parkinson's Disease Rating Scale (UPDRS), part IV, items         32 (duration of dyskinesias: 0=none, 4=76-100% of the waking         day) and 33 (disability of dyskinesias: 0=not disabling,         4=completely disabling) will be a secondary outcome measure.         This scale is a traditional scale used in PD for many years and         these items have been utilized in most LID studies.     -   Cognitive Scales: Global caregiver impression, depression and         other scales will be employed to measure the mental status         benefits of ER amantadine.

Statistical Methods

Efficacy Analyses: The efficacy analysis population will include all randomized and dosed subjects who provide at least one post-baseline efficacy assessment. For the efficacy endpoint of UDysRS score, the change from baseline to week 8 will be analyzed using an analysis of covariance (ANCOVA) model with treatment group as a factor and the UDysRS baseline value as a covariate. The primary analysis will compare the 260 mg ADS-5102 group to the placebo group using a two-sided test at the 5% level of significance. If the primary comparison is statistically significant (p<0.05), then the 340 mg and 420 mg ADS-5102 groups will be compared to placebo, also using a two-sided test at the 5% level of significance.

The secondary endpoints will be analyzed using the same types of ANCOVA models as described for the primary endpoint. All secondary comparisons between treatment groups will be performed using two-sided tests at the 5% level of significance. A last observation carried forward (LOCF) approach will be utilized for missing data. The primary efficacy analysis will be repeated for the per-protocol population, a subset of the efficacy analysis population who provide week 8 efficacy assessments.

Safety Analyses: The safety analysis population will include all randomized subjects who receive at least one dose of study drug. All safety endpoints will be analyzed from the time of first dose through the completion of follow-up (or 2 weeks following the last dose of study drug). A safety analysis will also be done on the safety reported during the first 2 weeks of study drug treatment, in order to assess tolerability of initial dosing with ADS-5102 amantadine ER.

Results: following improvements are expected from this study are shown in the table below. Additional endpoints are described that

-   -   Significant (20-60%) reduction in dyskinesia score measured by         acceptable primary endpoint (e.g., UDysRS)     -   Increase in ON time without troubling dyskinesia by 20-60%     -   Improvement in UPDRS from 5% to 20%.     -   Improvement in Parkinson's fatigue (FSS) from 5% to 60%.     -   Improvement in mood by PGI from 5% to 20%.

% Clinical Instruments for Effect (Placebo - Dyskinesia Active/Placebo) Range of Scores Unified Dyskinesia 5-60% 0-104 (4 parts, 26 items Rating Scale total, each 0, normal-4, (UDysRS) severe) Unified Parkinson's 5-20% Disease Rating Scale (UPDRS, MDS revision) Part IV 5-60% 0-24 (6 items, each 0, normal-4, severe) Part IV, dyskinesia 5-60% 0-8 (2 dyskinesia items, 4.1 items only and 4.2, each 0, normal-4, severe) Parkinson's Disease 5-40% 0-100% (on time without Home Diary dyskinesia or with (Hauser et al) nontroublesome dyskinesia)

EXAMPLE 12 Simulated Pharmacokinetic Characteristics of Amantadine ER Formulations with a Delayed Release Coat Suitable for Night Time Administration

Objective: The objective is to evaluate the pharmacokinetic profile of two alternative ER formulations of amantadine suitable for nighttime administration—Formulation 1, which is the formulation tested in Example 7, and Formulation 2, which is the formulation tested in Example 7, but with a delayed release over coat on top of the extended release coat.

Plasma concentration-time profiles from healthy volunteers, who received multiple doses of the ER and IR formulations of amantadine per study procedures described in Example 7 (ADS-5101-MD-104), were used to develop a pharmacokinetic model describing each of the two formulations. This study was an open-label, randomized, two-treatment, two-period, two-way crossover study comparing once-daily amantadine ER capsules and twice-daily amantadine IR tablets in 26 healthy, adult male and female volunteers. Complete data from 24 individuals were used in this exercise. Blood samples for pharmacokinetic evaluation were collected after single dosing on Day 1 and at steady state on Day 9. In the first step of the analysis, WinNonlin 5.2.1 (Pharsight Corp., Mountain View, Calif.) was used to fit a one-compartment model with first-order input and first-order output, weighted 1/y (where y is the amantadine plasma concentration), to each individual's plasma concentration-time data obtained after single (Day 1) and repeated (Day 9) dose administration of amantadine IR and ER; the fitting was done separately for both formulations, but simultaneously for both days. Modeling assumptions employed include dose proportionality and constant clearance as a function of time.

The model is described by the following equation

$\begin{matrix} {C = {\frac{FD}{V\left( {k_{a} - k} \right)}\left\lbrack {{\exp \left( {- {k\left( {t - t_{{lag})}} \right)}} \right)} - {\exp \left( {- {k_{a}\left( {t - t_{{lag})}} \right)}} \right)}} \right\rbrack}} & {{Equation}\mspace{14mu} 1} \end{matrix}$

where C is the plasma concentration, F is the absolute bioavailability, D is dose, V is the volume of distribution, k_(a) is the absorption rate constant, k is the elimination rate constant, t is time, and t_(lag) is the lag time of absorption. The goodness of fit was verified by comparing the individual model predicted and observed concentration-time data from Study ADS-5101-MD-104. After Equation 1 was fitted to each individual's plasma concentration-time data, model parameter estimates of V/F, k_(a), k, and t_(lag) were obtained for each of the 24 subjects. The goodness of the prediction at steady state was confirmed by comparing the observed data and predicted steady-state concentrations of amantadine obtained after daily dosing of 200 mg as the ER and IR formulations (Day 9).

In the second step of the analysis, individual model parameter estimates were used to simulate steady-state concentration-time profiles for each individual for both formulations by reinserting the individual parameter estimates into Equation 1, and summing the contribution of 7 sequential days of dosing, according to the following dosing regimens:

-   -   1. Once Daily (QD) dosing of 200 mg of the ER Formulation 1 to         steady state     -   2. Once Daily (QD) dosing of 200 mg of the ER Formulation 2 to         steady state

Results: FIG. 7 shows the simulated steady state plasma concentration time profiles for the two ER amantadine formulations. (Amantadine blood plasma concentrations are shown on the y, time of day on the x-axis.) As shown in FIG. 7, the ER amantadine formulation 2 administered once daily at night results in about a 4 hour delay in achieving peak plasma concentration at steady state relative to formulation 1. Thus, a formulation comprising a delayed release coat on top of the extended release coat has a very favorable pharmacokinetic profile in that it maximizes the daytime plasma exposure to amantadine whilst minimizing night plasma exposure at steady state.

While preferred embodiments of the present invention have been shown and described herein, such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. All references cited herein are incorporated herein by reference in their entirety. 

We claim:
 1. A method of administering a dose of a drug selected from the group consisting of amantadine and pharmaceutically acceptable salts thereof to a human subject orally, once daily at a time such that the drug does not interfere with sleep, wherein the dose consists of (i) 220 mg to 445 mg of the drug and at least one excipient, wherein at least one of said excipients modifies the release of the drug to provide an extended release form, and wherein administration of the dose provides a Tmax of 6 to 18 hours as measured in a single dose human pharmacokinetic study and once daily administration provides a C-ave-8-12 hrs to C-ave-0-8 hrs ratio of 1.1 to 2.0 as determined in a multiple dose human pharmacokinetic study.
 2. A method of reducing sleep disturbances in a patient undergoing amantadine therapy comprising orally administering to said patient once daily, at a time such that the amantadine does not interfere with sleep, a dose consisting of (i) 220 mg to 445 mg of a drug selected from the group consisting of mantadine and pharmaceutically acceptable salts thereof and (ii) at least one excipient, wherein at least one of said excipients modifies the release of the drug to provide an extended release form, and wherein administration of the dose provides a Tmax of 6 to 18 hours as measured in a single dose human pharmacokinetic study and once daily administration provides a C-ave-8-12 hrs to C-ave-0-8 hrs ratio of 1.1 to 2.0 as determined in a multiple dose human pharmacokinetic study.
 3. The method of claim 1 or claim 2, wherein administration of the dose provides a Tmax of 6 to 9 hours as measured in a single dose human pharmacokinetic study.
 4. The method of claim 1 or claim 2, wherein administration of the dose provides a Tmax of 8 to 18 hours as measured in a single dose human pharmacokinetic study.
 5. The method of claim 4, wherein administration is 0 to 4 hours before bedtime.
 6. The method of claim 1 or claim 2, wherein administration of the dose provides a Cmax of 1.0 to 2.8 ng/ml per mg amantadine and an AUC0-inf of 40 to 75 ng*hr/ml per mg amantadine as determined in a single dose human pharmacokinetic study.
 7. The method of claim 1 or claim 2, wherein once daily administration of the dose provides a steady state plasma concentration profile characterized by a Cmax of 2.4 to 4.2 ng/ml per mg of amantadine as determined in a multiple dose human pharmacokinetic study.
 8. The method of claim 1 or claim 2, wherein once daily administration of the dose provides a steady state plasma concentration profile characterized by a Cmin of 1.1 to 2.6 ng/ml per mg of amantadine as determined in a multiple dose human pharmacokinetic study.
 9. The method of claim 1 or claim 2, wherein once daily administration of the dose provides a steady state plasma concentration profile characterized by an AUC0-inf of 44 to 83 ng*hr/ml per mg of amantadine as determined in a multiple dose human pharmacokinetic study.
 10. The method of claim 1 or claim 2, wherein at least some of the drug is in an immediate release form.
 11. The method of claim 1 or claim 2, wherein at least 50% of the drug is in the extended release form.
 12. The method of claim 1 or claim 2, wherein at least 75% of the drug is in the extended release form.
 13. The method of claim 1 or claim 2, wherein at least 90% of the drug is in the extended release form.
 14. The method of claim 1 or claim 2, wherein the dose provides a single dose AUC0-inf per mg amantadine that is equivalent to that of a 100 mg tablet of an immediate release formulation of amantadine HCl.
 15. The method of claim 1 or claim 2, wherein once daily administration of the dose maximizes the daytime plasma exposure to amantadine while minimizing night plasma exposure at steady state.
 16. The method of claim 1 or claim 2, wherein once daily administration of the dose provides maximum benefit in morning hours.
 17. The method of claim 1 or claim 2, wherein the dose is therapeutically effective for the treatment of Parkinson's disease.
 18. The method of claim 1, wherein the human subject is being treated for Parkinson's disease.
 19. The method of claim 2, wherein the patient is being treated for Parkinson's disease.
 20. The method of claim 1, wherein the human subject suffers from dyskinesia.
 21. The method of claim 2, wherein the patient suffers from dyskinesia.
 22. The method of claim 20 or claim 21, wherein the dyskinesia is levodopa induced dyskinesia.
 23. The method of claim 20 or claim 21, wherein the method reduces the frequency or severity of dyskinesia.
 24. The method of claim 1 or claim 2, additionally comprising administering to the subject or patient a pharmaceutically effective amount of levodopa.
 25. The method of claim 1 or claim 2, wherein the dose is administered at a therapeutically-effective dose from the onset of therapy.
 26. The method of claim 25, wherein the therapeutically effective dose of amantadine or a pharmaceutically acceptable salt thereof is 220 mg to 445 mg per day.
 27. The method of claim 1 or claim 2, wherein the extended release form is an osmotic dosage form.
 28. The method of claim 1 or claim 2, wherein the drug is 40% to 65% of the dose. 